body1
stringlengths 20
4.1k
| body2
stringlengths 23
4.09k
|
|---|---|
I'm using PHP to connect with a SQL database using sqlsrv drivers. However, I've run into a problem: $string = "Home"; $DBH->prepare( "INSERT INTO table_name (column_name) VALUES ('" .$string. "')" ); $DBH->execute(); How come this works? $string = "Home's"; $DBH->prepare( "INSERT INTO table_name (column_name) VALUES ('" .$string. "')" ); $DBH->execute(); But this doesn't? The SQL database doesn't seem to accept the apostrophe in the $string variable. In the past I would use mysql_real_escape_string but that isn't an option. | If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example: $unsafe_variable = $_POST['user_input']; mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')"); That's because the user can input something like value'); DROP TABLE table;--, and the query becomes: INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--') What can be done to prevent this from happening? |
I am thinking about buying Tasker, and swype. If I purchase these apps, will I need to pay for them on each device? Or will a single purchase allow me to install on all my devices? | On the iPod Touch/iPhone, since it is tied to your iTunes account, I am quite sure you can have your bought apps on multiple devices you own (can't test though, iPod Touch was stolen). However, now I have the Motorola Droid, and am waiting for a tablet, and am considering getting a Nook and rooting it to run my own apps. Question is, if you buy an app on the marketplace, how is the security done: Is it tied to your Gmail account so you can share it between devices you own? Is it tied to the device? (Don't break/replace your phone!) As long as it's installed, you're OK? (If you uninstall, or wipe your device, it's gone). I assume 3 is highly unlikely, though a possibility, so leaving it here as a potential answer to my question. |
i am trying to pass some values in to a function and compare some values and get the array list. calling the Collect function in Dbhand class. TextView result = (TextView) findViewById(R.id.textviewres); result.setText(dbhand.collect( getIntent().getExtras().getString("temple_type"), getIntent().getExtras().getString("notemples")) ); collect() Function in dbhand class. public String collect(String temptype, String limit){ SQLiteDatabase ourDatabase = this.getWritableDatabase(); String result=""; String []column =new String[]{KEY_ID,KEY_TMPNAME,KEY_TMPTYPE,KEY_LATITUDE,KEY_LONGITUDE,KEY_IMGNAME,KEY_YEARBUILD,KEY_ADDRESS,KEY_CITY,KEY_EMAIL,KEY_WEB,KEY_TEL1,KEY_TEL2,KEY_DESCRI}; Cursor c=ourDatabase.query("templ", column, null, null, null, null,null, limit); c.moveToFirst(); int iKEY_ID = c.getColumnIndex(KEY_ID); int iKEY_TMPNAME= c.getColumnIndex(KEY_TMPNAME); int iKEY_TMPTYPE= c.getColumnIndex(KEY_TMPTYPE); for (c.moveToFirst();!c.isAfterLast();c.moveToNext()){ if (c.getString(iKEY_TMPTYPE) == temptype){ result = result+c.getString(iKEY_ID)+"\t\t"+c.getString(iKEY_TMPNAME)+"\t\t"+c.getString(iKEY_TMPTYPE)+" \n"; } } return result; } i didn't get any error, since the if condition is not compared. it does not return any value. can anyone help me to fix this plz. | I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug. Is == bad? When should it and should it not be used? What's the difference? |
I am forcing HTTPS and redirecting to subdirectory with: RewriteCond %{HTTPS} off RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI} [R=301] RewriteCond %{HTTP_HOST} ^domain.com$ [NC,OR] RewriteCond %{HTTP_HOST} ^www.domain.com$ RewriteRule (.*) /www_domain_com/$1 and all is working, but http://www.domain.com. I see in browser address bar: https://www.domain.com/www_domain_com/. My goal is to remove this subdirectory from url and have ssl in all requests and all requests redirected to that subdirectory. | This is a about Apache's mod_rewrite. Changing a request URL or redirecting users to a different URL than the one they originally requested is done using mod_rewrite. This includes such things as: Changing HTTP to HTTPS (or the other way around) Changing a request to a page which no longer exist to a new replacement. Modifying a URL format (such as ?id=3433 to /id/3433 ) Presenting a different page based on the browser, based on the referrer, based on anything possible under the moon and sun. Anything you want to mess around with URL Everything You Ever Wanted to Know about Mod_Rewrite Rules but Were Afraid to Ask! How can I become an expert at writing mod_rewrite rules? What is the fundamental format and structure of mod_rewrite rules? What form/flavor of regular expressions do I need to have a solid grasp of? What are the most common mistakes/pitfalls when writing rewrite rules? What is a good method for testing and verifying mod_rewrite rules? Are there SEO or performance implications of mod_rewrite rules I should be aware of? Are there common situations where mod_rewrite might seem like the right tool for the job but isn't? What are some common examples? A place to test your rules The web site is a great place to play around with your rules and test them. It even shows the debug output so you can see what matched and what did not. |
When a bus stops suddenly, I can "feel" a force pushing me. This is exactly as if someone really pushed me. Same is the case while doing a turn in a car, I can "feel" a force pushing me away from the centre. Also, why don't we feel the inward centripetal force but only the outward centrifugal force? If its only because of inertia, then why aren't they considered real forces since inertia is a fundamental property of matter. Everywhere I've read it says that pseudo forces are only incorporated to validate Newton's second law in non - inertial frames. But if they're not actual physical forces, then what is the force that I "feel"? Is there any other cause for pseudo forces other than inertia? | What is the underlying explanation behind ? The popular example of the bus: Lets say you are standing in a bus and the bus is moving with a constant velocity, we can therefore agree that you are in an inertial reference frame and therefore the law of inertia applies in your reference frame. However, as soon the bus decelerates you feel a "push" forward, moreover the frame is no longer inertial, at this point we agree that the law of inertia doesn't hold for that frame since you changed the state of your motion while no force is acting on you in your frame. Consequently, in order to make up for the "discrepancy" between the law of inertia and such situations we introduce a pseudo force (stating that this is the force that caused us to change states) in order to be able to effectively use Newtonian mechanics in a broader domain. This is the popular explanation as to why pseudo forces are introduced, however no one really touches on to the underlying principles of the occurrence of a pseudo force, so I'm looking forward for a more in depth explanation into the nature of a pseudo force (i.e why it occurs from a physical perspective?), rather than just saying that we introduce it in non-inertial reference frames, for reasons similar to the above. If we assume its nothing more than just a human correction used for mathematical and physical analysis, and simultaneously we can't say that inertia is the reason we tend to fall forward in the situation stated above since it is a non-inertial frame, then what would be the explanation exactly to such tendency of changing states of motion in an example like the above |
I would like to take sequential numbers up a level and only apply it to features of a certain type. Say I have two feature types, black and white features, and it's denoted by the field "Type". I want my sequential numbers code to skip all white features and pick up where it left off with the last black feature. I'm sure it's some type of If/Then statement but i can't figure it out. Here's the basic code where it returns sequential numbers by my sort field, which works just fine: import arcpy sortFeat = r"P:\path\Receivers.shp" #featurepath sortField = 'Ycoord' #Base Field to sort, which is idField = 'R_ID' #Field to populate sequential numbers rec=0 def autoIncrement(): global rec pStart = 36 #number of features pInterval = 1 if (rec == 0): rec = pStart else: rec -= pInterval return "R" + str(rec) rows = arcpy.UpdateCursor(sortFeat, "", "", "", sortField) for row in rows: row.setValue(idField, autoIncrement()) rows.updateRow(row) del row, rows print "Finish" So how can i make this only apply to certain attribute type and not all within the layer? I am using Python 3, but this currently only works in a 2.7 environment. | I am needing to auto increment a field based on groups within a feature class. I have 8 plots within a given polygon and I need to assign them an ID from 1-8 for each set of plots within each polygon. The polygon would have its own unique ID number to be used to group the plots. I assume it would be an alteration of this: rec=0 def autoIncrement(): global rec pStart = 1 pInterval = 1 if (rec == 0): rec = pStart else: rec = rec + pInterval return rec |
My kid's geometry classmate tried to use the following "theorem" in a proof: If a quadrilateral has a pair of opposite sides congruent and a pair of opposite angles congruent, it's a parallelogram. The teacher (correctly) didn't allow this, as they hadn't proven the "theorem" in class. The teacher, moreover, conjectured but could not prove that the "theorem" was in fact false. Is it? | I’m sorry I couldn’t upload a photo, so I’ll try to explain it as best as I can. The quadrilateral has a pair of opposite and equal sides, and has a pair of opposite equal angles (85 degrees in the question). Can I say this is a parallelogram or not? I tried drawing a shape with those conditions that is not a parallelogram and I failed. Thanks in advance, and again sorry for not having a photo and I hope I explained it well enough. |
please I need help for this how I can fix this issue in MySQL showing unreadable characters something like that الخطة الذهبية I change all the table to utf-8_generalc after that I edit manually the word in the database it passed is ok I can read it in the database. but on the site it give ??????????. if I fixed again the backend it becomes readable in the site but it comes again in database like that الخطة الذهبية | I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1. Where exactly do I need to set the encoding/charsets? I'm aware that I need to configure Apache, MySQL, and PHP to do this — is there some standard checklist I can follow, or perhaps troubleshoot where the mismatches occur? This is for a new Linux server, running MySQL 5, PHP, 5 and Apache 2. |
I'm rebuilding a site that will have both US and UK versions. Now the US and the UK version will be identical content, just allowing for variations in spelling i.e) Color vs colour. Now while there are a few ways of achieving this I can't think of a method I particularly like. First Option : Have duplicate content spelt differently and serve it up to visitors based on location. While straightforward enough, the site is very large, has a very involved CMS already and I just know that this option is going to be opening a massive can of worms for me later down the road. It also seems like an excessive amount of work to change a few characters. Second Option : Write some code to run string comparison and change the spelling based on location. While this would certainly work better, based on preliminary research there are about 1,700 spelling variations between UK-English and US-English. So when testing this idea even the most optimized function I can write has to run on every word, in every text node. Unsurprisingly I tried two different solutions, one in javascript, second in PHP and both are going to be way too slow to be used. The only way I could make this work, is if I only changed the spelling of key content, so ran it on all h1-h6 tags for example, but this isn't really good enough. So is there a better way than duplicating all site content? Edit : Reading the post I'm currently duplicating, it seems to me that the duplicate question, is regarding the best way to serve different content for multiple languages. Rather than exploring ways to avoid having duplicate versions of text in the US-UK case. Suggested amendments for relevancy, or should I move the question to this post? | I'm developing a PHP application and I'm wondering about the best way to include multi-language support for users in other countries. I'm proficient with PHP but have never developed anything with support for other languages. I was thinking of putting the language into a PHP file with constants, example: en.php could contain: define('HZ_DB_CONN_ERR', 'There was an error connecting to the database.'); and fr.php could contain: define('HZ_DB_CONN_ERR', 'whatever the french is for the above...'); I could then call a function and automatically have the correct language passed in. hz_die('HZ_DB_CONN_ERR', $this); Is this a good way of going about it? -- morristhebear. |
To define $\mathbb{R}$, one approach is to start with $\mathbb{N}$ and then systematically introduce $\mathbb{Z},$ $\mathbb{Q}$, and then $\mathbb{R}$. Alternatively, we define $\mathbb{R}$ using its axiomatic definition that it is a complete ordered field. And then, we can construct $\mathbb{N}$, $\mathbb{Z}$ and $\mathbb{Q}$ within $\mathbb{R}$. Now, $\mathbb{C}$ is introduced in the first way, by making $\mathbb{R}^2$ as a field. Can we follow the latter approach of defining $\mathbb{C}$ axiomatically, and then construct $\mathbb{R}$ inside it? | Sometimes it is useful to consider $\Bbb C$ as our primitive and identify $\Bbb R$ as a subset of $\Bbb C$. Thus we can define $\Bbb R$ (or at least a set with all of the interesting properties of $\Bbb R$) from $\Bbb C$. This suggests to me that there is some way of constructing $\Bbb C$ without first constructing (or taking as a primitive) $\Bbb R$. However, I've never seen such a construction of $\Bbb C$ (a quick Google search didn't provide me one, either). I've the Cayley-Dickson construction and the matrix construction many times, but are they the only known ways of constructing $\Bbb C$? My question: Is there a way to construct the set of complex numbers without already having (or first constructing) the real numbers? |
I am trying to add elements to a list here is my parent class public class TodoParent { public String ParentTitle; public Integer ParentId; public List<ToDoModel> mChildList; public long EpochTime; public TodoParent(String mTitle,List<ToDoModel> childModels) { this.ParentTitle = mTitle; this.mChildList = childModels; } public TodoParent() { } public String getParentTitle() { return ParentTitle; } public Integer getParentId() { return ParentId; } public List<ToDoModel> getmChildList() { return mChildList; } public void setParentTitle(String title) { ParentTitle = title; } public void setParentId(Integer mId) { ParentId = mId; } public void setmChildList(List<ToDoModel> list) { mChildList = list; } } Here is the situation where i need to add element @Override public void applyTexts(String header, String footer, String listType, String timeOfDay, int priotity,long mEpochtime) { //Toast.makeText(this,(String) timeOfDay, Toast.LENGTH_SHORT).show(); ToDoModel toDoModel = new ToDoModel(); TodoParent todoParent = new TodoParent(); toDoModel.header = header; toDoModel.footer = footer; toDoModel.task = listType; toDoModel.tod = timeOfDay; toDoModel.priorityVal = priotity; toDoModel.epochTime = mEpochtime; toDoModel.id = toDoModelList.size() + 1; todoParent.ParentTitle = footer; todoParent.mChildList.add(toDoModel); todoParent.EpochTime = mEpochtime; Toast.makeText(getActivity(), "New List Item Added", Toast.LENGTH_SHORT).show(); //mAdapter.add(toDoModelList.size(), toDoModel); parentAdapter.add(todoParentList.size(),todoParent); //input.add("To Do New1"); } todoParent.mChildList.add(toDoModel) is not working. How can I add toDoModel to mChildList ? I am new to java and this is something i am working on as a training. So any help is appreciated.Thankyou | What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them? What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely? |
I have put my question here because this is already anwered. | Show if is true or false: if $(f_n)$ converges uniformly to $f$, and $f_n$ is uniformly continuous for all $n$ then $f$ is uniformly continuous I think is true. My attempt to prove it: if $(f_n)\to f$ uniformly then we can write $$(\forall\varepsilon>0)(\exists N\in\Bbb N)(\forall x\in\mathcal D):|f_n(x)-f(x)|<\varepsilon,\quad\forall n>N\tag{1}$$ and cause all $f_n$ are uniformly continuous $$(\forall\varepsilon>0)(\exists\delta>0)(\forall x,y\in\mathcal D):|x-y|<\delta\implies|f_n(x)-f_n(y)|<\varepsilon,\quad\forall n\in\Bbb N\tag{2}$$ and I want to prove that both conditions implies $$(\forall\varepsilon>0)(\exists\delta>0)(\forall x,y\in\mathcal D):|x-y|<\delta\implies|f(x)-f(y)|<\varepsilon\tag{3}$$ where $\mathcal D$ is the domain of all of them (cause I have the previous knowledge that uniform convergence of continuous functions implies that the limit function is continuous). Then from $(3)$ I can write $$|f(x)-f(y)|=|f(x)-f_m(x)+f_m(x)-f(y)|\le |f(x)-f_m(x)|+|f_m(x)-f(y)|$$ Then I will use some $m$ that holds $(1)$ for some $\frac{\varepsilon}{3}$. And from $(2)$ I will use the $\delta$ that holds for the same $\frac{\varepsilon}{3}$. If $|f(y)-f_m(y)|<\frac{\varepsilon}{3}$ then $f(y)<f_m(y)+\frac{\varepsilon}{3}$. And then finally I can write: $$\begin{align}|f(x)-f(y)|&\le|f(x)-f_m(x)|+|f_m(x)-f(y)|\\&<\frac{\varepsilon}{3}+|f_m(x)-f_m(y)-\frac{\varepsilon}{3}|\\&<\frac{\varepsilon}{3}+|f_m(x)-f_m(y)|+\frac{\varepsilon}{3}\\&<\frac{\varepsilon}{3}+\frac{\varepsilon}{3}+\frac{\varepsilon}{3}=\varepsilon\end{align}$$ then it proves that exists a $\delta$ such that $|f(x)-f(y)|<\varepsilon$ for some $\varepsilon$ in the required conditions. Now, can you check my proof, telling me if it is right or if it lacks something? Thank you in advance. |
In The Above ScreenShot there is some pop-up thats i will get when open some application. please kindly solve my problem how to close its permanently. I am Using 18.04 LTS How to trun its close Please Note:- Already Remove Social Account And Also done Reset of Gnome then Also Its not Solve. | I recently upgraded from 17.04 to 17.10. The GNOME Calendar application displays a popup requesting my password for my linked Google account. It does so whenever launched explicitly, and at times on its own. When I type my (correct) password, the popup just reappears as if the password wasn't incorrect. The only way to dismiss the popup is to press the Cancel button. I can see my Gmail events in the calendar, so it does seem to sync. I tried removing my Google account from Settings -> Online accounts and re-adding it, with no change. If it's any help, I am using Google's two-factor authentication. Also note that Thunderbird does not seem to have this issue. |
I have added a background image using a tutorial on YouTube. it shows up just fine in my camera view but does not show up when I render the animation or render my viewport. The entire viewport shows up as white | First time I've used cycles rendering engine. I'm using a movie clip as the background in short animation. Selected RBGA under Property Tab, and Transparent under Film Tab. It looks good and individual frames in OpenGL active viewport render, and looks fine. When I try to get it to spit out PNG files of the finished animation the objects render out fine, except no movie clip background as Blender Render engine did when using Paper Sky setting. Operator error, or am I trying to do something Cycles won't do? Haven't found an answer in my searches so far. Can anyone point me in the right direction please. Addition: I think I found my problem after a couple more hours of research. Post should read "operator ignorance" instead of operator error. Too tired to try the solution tonight, everything looks better in the morning. Thanks anyway. Sorry, I just saw your posts. Really tired. Much appreciation. |
Prove that $A$ is invertible whenever $A$ is a $3\times3$ matrix with $$A^3 −A^2 + 2A−3I = 0.$$ This is another past exam paper question I'm stuck on. | The $2 \times 2$ matrix ${A}$ satisfies ${A}^2 - 4 {A} - 7 {I} = {0}$ where ${I}$ is the $2 \times 2$ identity matrix. Prove that ${A}$ is invertible. I have tried to solve it like a quadratic, but that doesn't work. Any help is appreciated! |
I want to import a .las file into QGIS 2.0.1. My guess is that I need to convert it into a format that is readable in QGIS. But how? I tried using LASTools. I downloaded it, but I don't understand how to use it? Any ideas? | Is there an easy path to visualizing LIDAR data in QGIS? I have some USGS LIDAR data in .las format downloaded from . This means I have both the .las and metadata in .xml format. I am aware , but not how to apply it to this task. I am running on Ubuntu 11.04 with QGIS 1.7.0-Wroclaw. A similar question for ArcGIS is: . I just need to get a sense of this data and the registration. Conversion to a DEM would be OK if I can visualize it. |
Prove that if $a,m$ are positive integers, then $$a^m\equiv a^{m-\phi(m)}\pmod m.\tag 1$$ If gcd$(a,m)=1$ then this is . Denote gcd$(a,m)=k$ and $a=xk,m=yk$ then we need to prove $$a^{m-\phi(m)}(a^{\phi(m)}-1)\equiv 0\pmod m\tag2$$ If gcd$(k,y)=1$ then $k\mid a^{m-\phi(m)}$ and $y\mid a^{\phi(y)}-1\mid a^{\phi(m)}-1$, hence $(2)$ holds. However, how to prove it if gcd$(y,k)\gt1$? | Problem: $(\forall a\in\mathbb{Z^+})(m\in\mathbb{Z^+}\to a^m\equiv a^{m-\phi(m)}\pmod{m})$ My work: Start by letting $m=p_1^{a_1}p_2^{a_2}\cdots p_r^{a_r}$. If $(a,p_i)=1$ for some integer $i$, then we have that $$ a^{\phi(p_i^{a_i})}\equiv 1\pmod{p_i^{a_i}} $$ by Euler's theorem. Since $\phi(p_i^{a_i}) \mid \phi(m)$, we have that $p_i^{a_i}\mid (a^{\phi(m)}-1)$ if $(a,p_i)=1$. Beyond this, I am stuck at the moment. |
A question about scope which I couldn't find online. If you would have a piece of code like: Function foo(myVar) { return myVar + 1 } Would myVar be bounded to the scope of foo? Thank you for your time. Edit: this is different from a question about scopes of variables in arguments because I wasn't sure if that would apply to arguments, since they weren't stated with var before them. | What is the scope of variables in javascript? Do they have the same scope inside as opposed to outside a function? Or does it even matter? Also, where are the variables stored if they are defined globally? |
I read that viruses are called intermediate between living and non-living particles. Well, if so, then where did they originate from? From living or non-living? If they originated from either living or non-living then how could they have both the characteristics of living and non-living? | My question is out of curiosity and got me thinking. How did viruses with the head, tail and tail fibres actually evolve? These viruses look more like machines than biological entities. Are there any theories to how these viruses evolved? |
Main part of the issue is self-explanatory, but there is a lot to add in for where this came from. Originally I was doing this because I (accidentally) Updated the Realtek audio drivers and it made many things worse - mic quality was awful (constant buzz) and audio quality is worse on the headset. I tried using system restore, which on its initial use gave me the error 0x8007045b. What i have tried doing: First thing I found was a website that basically linked this error to a mistake in windows that closed a service, then wanted to use it so caused an error. the fix for this was meant to be to run system restore in WinRE. I then found that it didn't exist on my PC, so I found an article for pulling it out of an image file downloaded through the media creation tool, and then after that ran system restore, which then gives this error instead. Another thing to note is that i have tried two separate restore points and both bring up the same error. Also I have used SFC and DISM for error checking and repairing errors. | Here is the error message: System Restore did not complete successfully. Your computer's system files and settings were not changed. Details: System Restore failed while restoring the directory from the restore point. Source: AppxStaging Destination: %ProgramFiles%\WindowsApps An unspecified error occurred during System Restore. (0x80070091) What I've tried so far: chkdsk /f /r C: (didn't work) tried running in safe mode the system restore (didn't work) tried with another system restore point (didn't work) |
I want to make a 3D thematic map with the different status' population data as the height in Python. I have the shapefile of the status and the population data, although I don't know how to set the population attribute data as the Z-axis. I want to make a map like the following. Is there a python package that allows the 3-D mapping of shapefiles such that I can specify an attribute as the Z value? | I have a Uniform Grid of 1KMx1KM squares as a shapefile with population data in each grid in a specific column as an integer. I would like to extrude each polygon based on the population and export the whole dataset using a python library. ArcScene can do this, but ArcPy can't hook into that program. Can someone recommend a python package to do this? It doesn't have to be dependent on ArcGIS Desktop. I was looking at matplotlib, but I can't figure out how to create 3D bar graphs. |
Would the following be a safe way of storing a user's password in a database? When registering: $salt=hash("sha512", rand()); $password=hash("sha512", $_POST["password"].$salt); insert_values_into_db; When logging in: $given_password=$_POST["password"]; $salt=get_salt_from_db; $correct_password=get_password_from_db; if(hash("sha512", $given_password.$salt) === $correct_password){ //Password is correct }else{ //Password is incorrect } Are there any blatantly obvious errors with this? | It is currently said that MD5 is partially unsafe. Taking this into consideration, I'd like to know which mechanism to use for password protection. This question, suggests that hashing multiple times may be a good idea, whereas suggests using salt. I'm using PHP. I want a safe and fast password encryption system. Hashing a password a million times may be safer, but also slower. How to achieve a good balance between speed and safety? Also, I'd prefer the result to have a constant number of characters. The hashing mechanism must be available in PHP It must be safe It can use salt (in this case, are all salts equally good? Is there any way to generate good salts?) Also, should I store two fields in the database (one using MD5 and another one using SHA, for example)? Would it make it safer or unsafer? In case I wasn't clear enough, I want to know which hashing function(s) to use and how to pick a good salt in order to have a safe and fast password protection mechanism. Related questions that don't quite cover my question: |
For a proof in my textbook it is asserted that if $d=(n,a), n=db, a=dc$ for suitable $b,c\in\mathbb{Z}$ then $(b,c)=1$. I am not very good with number theory and this boggles me a bit. I am sure it is not so difficult to realize but I am stumped right now. Could someone please help me out? | Could someone please help me with this proof? Suppose that $a, b \in N$, and $d = \gcd(a, b)$. Since $d$ divides $a$, we have $a = de$ for some integer $e,$ and similarly $b = df$ for some integer $f$. Prove that $\gcd(e, f) = 1$. I understand why it works. Since d is all the common factors of $a$ and $b, e$ and $f$ had no common factors, therefore the $\gcd(e,f) = 1$. But how do I prove this? Thanks in advance. |
Similar to this question, but different reasoning: And I feel like I have to ask a new question so that Jeff will notice. Someone writes a question. Suppose it's a SQL one. They don't provide version information, so then I upvote an answer that runs nicely in SQL 2008. Then the question is edited to say it's actually SQL 2000. All I can do is put a comment on the answer I upvoted, saying that my upvote only applies because the code is fine in SQL 2008. But in the meantime, the answer that works on SQL 2000 is left languishing somewhere else, possibly never notice because the asker hasn't accepted it. So unless the person who Googles/Bings/Altavistas the solution notices the 15th comment where I write "This doesn't work on SQL 2000", and only notices the 100 upvotes (oh, sorry - I had said 'SQL', so that's not going to apply), the searcher is going to feel misled by this site. So please, let me know if a question is edited (so that I can change my own answers), and so let me change votes if I feel it's necessary. | Recently I downvoted the answer because I thought it didn't answer the question. Not very uncommon reason to downvote, isn't it? But then the guy, who asked the question, edited his question and I realized that the answer I downvoted actually answers it and deserves an upvote instead! But I couldn't do it. I could do it if the answerer had edited his post. As I understand, the rationale of changing vote after edit is the following. If I came to the question page for the first time after the edit of the answer, I would've upvoted it instead of downvoting. But why doesn't the same rationale hold for the cases when the question is edited? Unless there's a good reason, I suggest to allow changing answer vote on question edits, not only on answer ones. |
Is it possible to start Ubuntu Desktop 18.04 always with Numlock on? In 16.04 it works with the file /usr/share/lightdm/lightdm.conf.d/99-numlockx.conf. | I am trying to force numlock to be on upon initial boot at the login screen on Ubuntu 12.04. The only solutions I have found so far switch numlock on only after initial login. I'm looking to force numlock to be on when the login screen is displayed, and before the user has logged in. Can anyone assist? |
What does it mean by a^b in real number system? How is it defined mathematically? It is clear in case of exponent being an integer. i.e., a real number a is multiplied b times where b belongs to Z If b is a rational..say b=p/q, then a^b can be interpreted as a^(1/q) multiplied p times. But how is it defined when b is irrational? | I've been reading through a course on exponential functions, starting from integer-valued exponents to rational ones as in: $x^r$ from $r\in \Bbb{N}$ to $\Bbb{Z}$, and combining them to rigorously construct for $r\in\ \Bbb{Q}$. Still, this book adresses high-schoolers, and therefore "summons" an extension of the exponential notation for real exponents. Is there any formal basis for this extension? Could it be related to the density of $\Bbb{Q}$ in $\Bbb{R}$ ? Or the limit of a sequence $(x^{(r_n)})$ where $(r_n)_{n=1}$ is a sequence of rationals that converge to $r$ a non-rational exponent? |
A friend of mine got an invitation for an interview late April, so he was thinking should he book the flight now, or wait until last few days, in case he was invited for another interview. However, waiting until last 4-5 days would increase the ticket price and in worst case may not have any seats available. | I am currently on the academic job market, and scheduling on-campus interviews with institutions that might want to hire me. Suppose I am invited to an on-campus interview at the University of X, and must travel there by air. They handle travel on a reimbursement basis: I buy the plane ticket, and then they reimburse me. However, the interview is a few weeks away. Since the job market sometimes moves fast, there is a chance that by the time of the scheduled interview, I may have already accepted another offer (say from the University of Y). Of course I should then decline the interview at X, but I would have already bought the plane ticket. How should I plan for this contingency? I could buy a refundable ticket to X. However, these are normally several times the price of a non-refundable ticket, and if I do end up traveling to X, they might balk at reimbursing me for such an expensive fare. I could buy a non-refundable ticket to X. If I end up not going there, I could ask X to reimburse me for the cost of the ticket (or at least the "change fee" charged by the airline to let me use the ticket's value for a future flight). However, I suspect they will be reluctant to reimburse me for a trip I'm not making, and might refuse to do so altogether, in which case I am out-of-pocket. I could wait until the last minute to buy a non-refundable ticket for X. But it may still be expensive for them (or may exceed their limits), and the most convenient flights may be sold out. I could contact University of X and ask them for guidance. I'm a bit hesitant to do this, as I am afraid that if I bring up the possibility that I might accept another position, they might think I am not seriously interested in theirs. Is there a standard way to handle this situation? This is in the United States, if it matters. |
This short story concerns an alien creature of some kind that is slowly feeding on the surface of its home planet. It must stay "in its lane" so to speak because others of its species feeds on either side of it. It encounters something in its path which turns out to be a probe from somewhere. The creature can't go around (due to the feeding rules) it so it attempts to go OVER it and ends up inside and is amazed to find itself immersed in "liquid food" (a formula culture provided to sustain any alien samples collected). It suddenly reproduces, even though the alien concedes it was not the right time to do so. AND the food bolsters its intelligence. It argues with its spawn, explaining that "they" must get to the planet's surface. One does but the other does not! Any ideas? | Trying to find title/author of story I read many years ago, around 1964. Story was written from the point of view of a snail like creature. The central character describes (stream-of-consciousness?) himself and other characters moving along a path in a constant search for food. The story ends with the main character falling into what turns out to be the fuel tank of a space ship. |
I am getting the message "Too many of your edits were rejected." while trying to add a tag wiki. Am I banned from such edits? Is the ban temporary or permanent? | First time I've got the following message on SO: Too many of your edits were rejected, try again in 7 days. Although, I have made ~50 accepted edits this day. I'm sure that should outweigh the ~5 rejected edits, right? My suggestion: bool allowEdit(USER u) { if(u.rejected * 5 > u.accepted) return(false); else return(true); } Think of it this way: if I do a 1000 accepted edits, and mess up on 5 [rejected], does that mean I should get banned for 7 days? Hmmm... There seems to be a bug; the message only appears when clicking edit from review. But otherwise, I can't edit , even when going to it from the homepage. |
First time using ubuntu. I installed 13.10 and now when i start up the system it prompts me for a login. I login just fine, but once it loads there are no icons or menu of any kind. I can left click and drag to make boxes, and i can access all the options from right clicking (such as New Folder, New Document, Change Desktop Background, etc.) but that is it. I've read some forums about people logging out and switching to 2D, but I don't seem to have that option. Any and all help is much appreciated. | When I login, nothing happens. I am presented with my desktop wallpaper. No Dash, no Launcher, nothing. |
I have installed Ubuntu 18.04 on a new HP EliteBook 850 G6. It is claiming it can't find the wifi adapter. The adapter works just fine in Windows 10, so the hardware is working. I installed it via the iso and requested third party driver installation. No dice. The light on the key for the wifi status is amber, and doesn't turn on or off when hitting fn + F11 button. Not sure what to do at this point as I've installed it twice now and still can't get it working. EDIT: added results of lspci and rfkill danp@danp-HP-EliteBook-850-G6:~$ lspci -nnk | grep 0280 -A3 3a:00.0 Network controller [0280]: Intel Corporation Device [8086:2723] (rev 1a) Subsystem: Intel Corporation Device [8086:0084] 3b:00.0 Non-Volatile memory controller [0108]: Intel Corporation Device [8086:f1a8] (rev 03) Subsystem: Intel Corporation Device [8086:390d] danp@danp-HP-EliteBook-850-G6:~$ rfkill list 2: hci0: Bluetooth Soft blocked: no Hard blocked: no | My wifi card is an Intel® Wireless-AX200 (802.11/a/b/g/n/ac/ax), Bluetooth® 5, and bluetooth is working. I've tried following various guides, however these drivers are apparently yet to make it into the kernel. Their product brief states linux is supported: And yet their driver page has no listing for them: sudo lshw -c network => mark@m-blade-2019:~$ sudo lshw -c network *-network UNCLAIMED description: Network controller product: Intel Corporation vendor: Intel Corporation physical id: 0 bus info: pci@0000:02:00.0 version: 1a width: 64 bits clock: 33MHz capabilities: pm msi pciexpress msix cap_list configuration: latency=0 resources: memory:cf300000-cf303fff *-network description: Ethernet interface physical id: 2 logical name: enx0050b6b47e72 serial: 00:50:b6:b4:7e:72 capabilities: ethernet physical configuration: broadcast=yes driver=cdc_ncm driverversion=22-Aug-2005 firmware=CDC NCM ip=192.168.1.17 link=yes multicast=yes I'm running kernel version Linux 5.0.0-13-generic, any help is greatly appreciated. EDIT: results of lspci -nnk | grep 00280 -A3: mark@m-blade-2019:~$ lspci -nnk | grep 0280 -A3 02:00.0 Network controller [0280]: Intel Corporation Device [8086:2723] (rev 1a) Subsystem: Intel Corporation Device [8086:0084] Kernel modules: wl, iwlwifi 03:00.0 Non-Volatile memory controller [0108]: Samsung Electronics Co Ltd NVMe SSD Controller SM981/PM981 [144d:a808] mark@m-blade-2019:~$ |
'Healthy Body and Me' or 'Healthy Body and I' which one is correct ? It's actually a name of the blog so I appreciate for your advice and also if you could explain why. Thanks | With the enthusiastic question of "Who wants ice-cream?", what is the more correct response? (Not) I. (Not) me. Neither response is a sentence. The first response of "(not) I" sounds stuffy, like it should be followed with an indignant sniff. The second sounds like American idiom and acceptable for casual speech. What do you say? |
According to : Yang–Mills theory is a gauge theory based on [...] any compact, semi-simple Lie group. But the symmetry group of Standard Model, i.e. ${SU(3)}\times{SU(2)}\times{U(1)}$, is not semisimple, due to the $U(1)$ factor, right? What am I missing here? | What is the motivation for including the compactness and semi-simplicity assumptions on the groups that one gauges to obtain Yang-Mills theories? I'd think that these hypotheses lead to physically "nice" theories in some way, but I've never, even from a computational perspective. really given these assumptions much thought. |
I am trying to prove that when $f$ is continuous for all non-negative real number and $$f(2^x)=f(3^x),$$ then $f$ is constant. If $f(2^x)=f(3^x)$ then from here I can say that $f(2^x/2^n)=f(3^x/3^n)$ and then I can use limit when $n\to\infty$, but I am not sure how to make connection with $f(x)$ function itself to prove. Could you give me any hints? Thanks in advance. | I need to show that the following function is constant: $f:(0,\infty)\to\mathbb{R}$, $f(2^x)=f(3^x)$ and $f$ is continuous. I need to find the value of $f(x)$. So I did something but I do not know how to continue. Let $x\to \log_2 x$ and we get that $f(x)=f(3^{\log_2 x)}$. Now, let $x\to 3^{\log_2 x}$ and we get that $f(3^{\log_2 x)}=f(3^{\log_2 3^{\log_2 x})}$. And so on. I think I need to find a rule. Do you have any idea? |
Prove: The integer p-1 is a quadratic residue of an odd prime p if and only if p congruent 1 ( mod4). That’s right?! | I came across this problem and I believe Lagrange's theorem is the key to its solution. The question is: Let $p$ be an odd prime. Prove that there is some integer $x$ such that $x^2 \equiv −1 \pmod p$ if and only if $p \equiv 1 \pmod 4$. I appreciate any help. Thanks. |
I am getting strange color noise in my diffuse direct passes. It shows up at the edges of the model, and at material boundaries on the model. It happens even with basic shaders (just diffuse mixed with gloss) but does not happen when diffuse and gloss are both gray, even with different values (or maybe it happens but just isn't visible.) I have never encountered this issue before, so I am very perplexed. Debugging so far: Does not seem to have anything to do with lights or edge settings. Happens with both normal and toon shaders. Only appears in diffuse direct, not glossy direct (or just isn't visible.) Is not visible in the combined pass, but makes problems when working with Diffuse Direct in the compositor. My main guess is that it has something to do with a render setting in Cycles. Anyone else run into this? Other render settings: Happens regardless of resolution Samples: 2,000 Clamp: Happens regardless of clamp value Pattern: Happens with both Sobol and Multi-Jitter Shadows, Reflective Caustics, and Refractive Caustics are all on Filter Glossy: 1.0 Bounces: 5 max/3 min, Diffuse 4, Glossy 4, Transmission 12, Volume 0 Film: Exposure 1, Transparent, Blackman-Harris, Width 1.5 Post Processing: Compositing and Sequence on, Dither 0.00 Turning down the Width for Filter type under Film reduces but does not eliminate the problem. | Is there any way to remove fireflies from the edges on a glossy direct pass? (At the very edges of the popcorn container and haloing the popcorn kernels in the front) I set the samples to 2000 and filter glossy: 0.5 in the render below. The light is set to multiple importance on. |
I have a long paragraph but i only want to show some portion of it. Is it possible to generate "..." after some words. for example, this is my paragraph. <div class="paragraph"> <p>Lore gypsum dolor sit met, con sec tetuer dip icings lite. Aeneid commodore ligula beget dolor. Aeneid mas- s. Cum socialist toque Pentiums lit something something</p> </div> and i want to show in the page like "Lore gypsum dolor sit me ...." | I have a webpage with an elastic layout that changes its width if the browser window is resized. In this layout there are headlines (h2) that will have a variable length (actually being headlines from blogposts that I don't have control over). Currently - if they are wider than the window - they are broken into two lines. Is there an elegant, tested (cross-browser) solution - for example with jQuery - that shortens the innerHTML of that headline tag and adds "..." if the text would be too wide to fit into one line at the current screen/container width? |
I tried differentiating under the integral sign which led me to: $$f'\left(y\right)=-\int_{0}^{\infty}e^{-xy}\sin^{2n+1}\left(x\right)dx\ =\frac{-\left(2n+1\right)!}{\prod_{k=0}^{n}\left(y^{2}+\left(2k+1\right)^{2}\right)}$$ where $$f\left(y\right)=\int_{0}^{\infty}e^{-xy}\frac{\sin^{2n+1}\left(x\right)}{x}dx$$ And now I'm stuck trying to evaluate $$-\int_{b}^{y\ }\frac{\left(2n+1\right)!}{\prod_{k=0}^{n}\left(t^{2}+\left(2k+1\right)^{2}\right)}dt=f\left(y\right)-f\left(b\right)$$ which, once I let $b$ approach $\infty$ and prove that I can set $y=0$ in the resulting expression, will lead me to the answer. I know the integral in $t$ is technically doable using partial fractions but I can't see how I can get an explicit expression in terms of $n$ (which I know exists) out of this approach. Here's the answer. $$\int_{0}^{\infty}\frac{\sin^{2n+1}\left(x\right)}{x}dx=\frac{\pi\left(2n\right)!}{2^{2n+1}\left(n!\right)^{2}}$$ | Here is a fun integral I am trying to evaluate: $$\int_{0}^{\infty}\frac{\sin^{2n+1}(x)}{x} \ dx=\frac{\pi \binom{2n}{n}}{2^{2n+1}}.$$ I thought about integrating by parts $2n$ times and then using the binomial theorem for $\sin(x)$, that is, using $\dfrac{e^{ix}-e^{-ix}}{2i}$ form in the binomial series. But, I am having a rough time getting it set up correctly. Then, again, there is probably a better approach. $$\frac{1}{(2n)!}\int_{0}^{\infty}\frac{1}{(2i)^{2n}}\sum_{k=0}^{n}(-1)^{2n+1-k}\binom{2n}{k}\frac{d^{2n}}{dx^{2n}}(e^{i(2k-2n-1)x})\frac{dx}{x^{1-2n}}$$ or something like that. I doubt if that is anywhere close, but is my initial idea of using the binomial series for sin valid or is there a better way?. Thanks everyone. |
I'm trying to get the number of digits of a number in javascript, but I'm running into some edge cases with the equations I've found online. Here's what I'm using, from . getNumDigits(val){ return val === 0 ? 1 : Math.floor(Math.log(Math.abs(val)) / Math.LN10 + 1); } But the problem with this is, if you put in a number like 1000, you somehow get a javascript rounding error where the value comes out like 3.999997 I've noticed that, as long as your number isn't between -1 and 1, you can just add 1 to the val in the Math.abs(val) and it will appropriately set the number of digits, but it just seems messy. I've tried just converting the val into a string, and getting the length, but that doesn't work in the case of, say, a decimal, where you're using something like 0.2 - as it will say the length is 3. What's a good equation / function to use? | Consider the following code: 0.1 + 0.2 == 0.3 -> false 0.1 + 0.2 -> 0.30000000000000004 Why do these inaccuracies happen? |
I have added a comment to , and I noticed that my comment contains a semicolon. I thought I added it by mistake, but the edit form doesn't show any semicolon. From where does the semicolon come? It is not automatically added, as the other comments don't have it, and the dash character is already added at the end of the comment, and before the username of who posted the comment. | I added a comment to but something strange is happening. The end code reads "); but SO decided to change that to ";);. I did not add a ; in front of the ). To further explain what's happening here, the following: "http://example.com/." http://example.com/. "http://example.com." http://example.com. "http://example.com" http://example.com renders as: |
I have been reviewing how to plot a line histogram on data of my results. I have searched and only see how to plot in bar histogram, but I have not seen any construction of one of lines in latex. I also searched for TikZ but I can not find it. Attached image of the type of histogram I want to do: Any idea what I can use? regards. | I managed to create a simple linear plot with pgfplots-manual (chapter 4.5.1) Now I want to replace the values of x-axis (1,2,3,4) with text, e.g.Test A, Test B, Test C, Test D. How can I do such a configuration? MWE: \documentclass[12pt,ngerman]{article} \usepackage{pgfplots} \pgfplotsset{width=7cm,compat=1.10} \begin{document} \begin{tikzpicture} \begin{axis} [ xlabel={Test}, ylabel={Mean} ] \addplot+[sharp plot] coordinates {(0,18.26) (1,21.47) (2,24.58) (3,24.95)}; \end{axis} \end{tikzpicture} \end{document} |
In Time of The Doctor, Time Lords gave The Doctor regeneration energy using which The Doctor regenerated. Does the 14th Doctor (commonly known as 12th) have any regeneration energy left? Can he regenerate again (using the same regeneration energy)? | In The Time of the Doctor, the Doctor says that he has a "new regeneration cycle". Does this mean he has another set of 12 regenerations, or just the one? |
I am using OSX Catalina. However, for quite some time, do not remember from which OSX, Preview stopped highlighting instances of a searched for word. As suggested in the answer to the post , if I choose `Table of Contents' in View, the sections of pages where the searched for word appears are displayed in the sidebar but the word is not highlighted. Also, in the top right corner of the Preview window, below the search box, there are two arrows to go forward/backward through the search results. These arrows remain greyed out and do not work. These issues are rather irksome. Is there any way out? | A problem has recently become much more prevalent for me when using Preview to search PDFs for text (using Command + F or the search box in the upper right). At first, everything generally seems to go fine: (as it should be) a list of thumbnails appears in the sidebar, indicating all of the pages that contain the search term. Generally, though not always, the term I search for will be highlighted on the first page that it occurs on. But, after this, things quickly start malfunctioning: Generally speaking, if I click on thumbnails lower on the list, Preview will take me to that page in the PDF (like it used to). But, it will no longer highlight the searched for terms. Instead, Preview will make a low-pitched beeping noise of the sort that occurs when one tries to perform some un-permitted action in a variety of mac situations. Furthermore, once this occurs, I cease being able to make any highlights at all in the document I am viewing with Preview. In fact, I can't even select any text any more. Below is a list of unsuccessful efforts to resolve this: Closing the side bar does not work to resolve this. x-ing out the search box in the upper right does not resolve this. Selecting the "Tools" menu and then "Text Selection" does not work either, nor does clicking on the text selection icon in the edit panel. If I quit preview and then re-open the PDF, I am able to highlight again. But, the problem will re-surface as soon as I try performing another search. Working with the same files in other PDF programs (e.g. Skim, Acrobat, etc.) poses no problems. I'm quite certain it isn't a problem with the underlying PDFs. None of the responses to resolve this. (indeed, I supplied one such response myself a while ago, but that trick and the others no longer work). I've used Preview for many years without problem. This issue started cropping up relatively recently for me, I believe within the past 3-4 months. I had hoped that upgrading to Catalina might resolve it, but it did not. I'd like to think I am fairly sophisticated with computers (I have a reputation of close to 8,000 on the main stackoverflow page), but I am baffled by this. I also don't have a good handle on how I can get diagnostic information or how I can create a reproducible example. Any leads on how to tackle this would be greatly appreciated. |
I'm doing a binary regression, with two predictors one binary and one continuous. I'm using the enter method. I want to know if my model can be significant when I compare it to the model with only the constant while at the same time all my predictors are not significant? Or there something wrong about my model? | My multiple regression analysis model has a statistically significant F value however all beta values are statistically non-significant. All the regression assumptions are met. No multicollinearity was found. Correlations among all predictors are all less than 0.60. What else might be the cause of the insignificant predictors? |
I'm trying to determine why these services consume 50% of my CPU for hours at a time each day. I cannot restart the services without error and killing the PID just restarts it in a few minutes and it's back to chewing through CPU. Using process explorer these are the DLL's that run under the PID in question. Windows 7 I take MS updates about once a month. Any ideas? | I installed Windows 7 fresh and installed SP1. Now, when I try to check manually for Windows Updates it just hangs on the Checking for updates screen. I tried running the tools in , but this did not fix the issue either: No matter what I do it just hangs on the "Checking for updates..." screen and goes no further. |
I am a newbie so maybe my question is not so shiny. I wont to install something (virtualbox) but I have to chose between the 32-bit version and the 64-bit version according to my OS. Problem is that I don't know/don't remember what type of OS it is from that point of view. So my question is the following: Is there any fast and easy way (for a beginner like me) to find out what kind of OS is using? Thank you! | I downloaded and installed Ubuntu from the official site. However, I don't know if I installed the 32-bit or 64-bit version. In Windows 7 I could right click My Computer and it listed which version it was. Is there an easy way to check in Ubuntu? |
I am not being able to find the specific product $\prod_{r=1}^{k} \left(1-\frac{1}{\sqrt {r+1}}\right)$ so to evaluate the given problem when $k \to \infty $. | Let $$a_n=\left(1-\dfrac{1}{\sqrt2}\right)\dots \left(1-\dfrac{1}{\sqrt{n+1}}\right),n\ge1$$ Then find $\lim_{n\to \infty} a_n$. How can I proceed? I am stuck at the first step. Please help. |
No SHA-1 collisions are actually known, though there are a number of cryptographic attacks to weaken it. But, how likely is it that, of all the SHA-1 hashes computed since the invention of the algorithm, there has been a collision? Not sure how to approach this, but it probably involves the Birthday Problem? (if there's a better SE to ask this in, let me know) | Given the , what is the complexity of finding a SHA-1 collision? Marc Steven's is still detailing about 260. Does the previous complexity still hold? |
Consider two natural numbers $a,b$. Prove that $a = b^m$ if $ \frac{a^n-1}{b^n-1} $ is natural for all $n \in N$. I tried to assume that there is exist some $k $, such : $a = b^m + k$, so i get $$\displaystyle \frac{\sum_{0}^{n}b^{n-i+m}k^i -1}{b^n-1}$$ but I guess I just waste my time. Need some good idea. | We can prove that there is no integer $n>1$ such that $2^n-1\mid 3^n-1$. This leads to the following question: Is it true that for every pair of primes $p<q$ there are only finitely many integers $n$ such that $p^n-1\mid q^n-1$? Are there two primes $p<q$ and an integer $n>p+q$ such that $p^n-1\mid q^n-1$?Is it true that if $n>6$ then $2^n-1\nmid 5^n-1$? Edit: Here are some examples: \begin{array}{ll} 2^{36}-1\mid 41^{36}-1, &3^{12}-1\mid 97^{12}-1,\\ 5^{6}-1\mid 37^{6}-1, &7^{4}-1\mid 151^{4}-1. \end{array} Now I prove there is no integer $n>1$ such that $2^n-1\mid 3^n-1.$ Proof: Denote $A=2^n-1$ and $B=3^n-1$. If $n$ is even then $3$ divides $A$ but not $B$, a contradiction. If $n$ is odd then $A\equiv -5\pmod {12}$. Since every prime greater than $3$ is $\equiv \pm1,\pm5 \pmod {12}$, some prime factor $p$ of $A$ must be congruent to $\pm5 \pmod {12}$. As $p \mid B$, we have $3^{n+1}\equiv 3 \pmod p$. Since $n+1$ is even, we get $(\frac{3}{p})=1$, a contradiction again. |
In Ubuntu 19.10 there's automatically converted GNOME's dash to dock. And, configuration: "settings -> dock": offers only option "Auto-hide the Dock", "GNOME Tweaks": can't configure any extension about dock. However, I need to hide it always, except when activity/search menu/screen is shown. As, it's pretty much annoying slowdown, when I want to press some button on the left side, and dock shows and covers application's buttons,... | The big dock on the left. In other versions you could escape Unity Launcher by going to GNOME, what now? GNOME tweaks is not showing it as an extension, even though it looks a lot like Dash to Dock. I see autohide options in settings, but no way to completely remove it and use the GNOME default. Edit: I'm not looking for vanilla GNOME, but simply to hide the dock. |
I have a column in database which have following value drop#drop#drop#drop#drop#drop#drop#drop and I want to get 7th number drop from this value. I not want to split the string. | Using SQL Server, how do I split a string so I can access item x? Take a string "Hello John Smith". How can I split the string by space and access the item at index 1 which should return "John"? |
>>> a = 1 >>> b = 2 >>> c = 3 >>> a+b is not c False Close python, start new session to be sure variables aren't being re-used or anything >>> a = 293 >>> b = 2 >>> c = 296 >>> a+b is not c-1 True Why are these different? 4 is not 4 - False (correct) 295 is not 295 - True (incorrect) EDIT: sorry I don't think I was clear in my question. i'm not asking if is not should be used for value comparison, or if it's equivalent to !=, I'm asking why it produces inconsistent results that vary based on the integer values being evaluated. | My has failed me. In Python, are the following two tests for equality equivalent? n = 5 # Test one. if n == 5: print 'Yay!' # Test two. if n is 5: print 'Yay!' Does this hold true for objects where you would be comparing instances (a list say)? Okay, so this kind of answers my question: L = [] L.append(1) if L == [1]: print 'Yay!' # Holds true, but... if L is [1]: print 'Yay!' # Doesn't. So == tests value where is tests to see if they are the same object? |
I would like to know whether or not a verb in its bare infinitive form can be used as the subject of a sentence. In other words, is it grammatically correct to say: Do what her/his mother asks is something a child has to learn. I have checked a few grammar books and none mentions this use (if any). Still, it does not necessarily exclude the case. Thanks. [Added] If possible, I would appreciate it if a reference source can be provided to support your input. Many thanks for the discussion. | Talk to him is what I did. (this sentence is from ) "Talk" is a verb here that is not in the imperative mood. I suppose, it's in the infinitive form. But then how can it stand alone, without "to"? What will be if we add "to" to "talk"? To talk to him is what I did. If we can do so, then what will difference be between the initial sentence and the new one with "to"? Maybe, there are some omitted words, after inserting which the sentence will immediately become understandable? I mean, maybe, there is an ellipsis? Thanks! To make it clearer: Upd.1: if we type "bare infinitive" in google, we can't find any sites that could explain the absence from "to" before "talk". Upd.2: Why can we replace "to talk" with only "talk" in "To talk to him is what I did." Upd.3: I have my own logic but I don't know whether it's right or not: 1) I think that without an ellipsis "Talk to him is what I did." is to look like "I did talk to him is what I did do." 2) Also I know that we can't use "to" before "read" in "What we must do is read the manual." because in the left part we don't have "to" before "do". By this logic, we can't use "to" before "talk" in "Talk to him is what I did." because in "what I did do" we don't have "to" before "do". Am I right or not? |
If a battery has 100mA-hour rating will two batteries connected in series have also 100mA-hour rating but at double the voltage? | When combining battery cells in series, the voltages of the cells are added to get the voltage of the final circuit. Do the mAh add up, or stay the same? For example, suppose you have two 3.7V cells, each with 200 mAh capacity. When connected in series, will the resulting battery will be a 7.4V, 200mAh battery? |
I know that $ax=1$ has a solution in $F$ so that every element must be a unit but then I'm not sure how to proceed. | I'm currently studying Polynomial Rings, but I can't figure out why they are Rings, not Fields. In the definition of a Field, a Set builds a Commutative Group with Addition and Multiplication. This implies an inverse multiple for every Element in the Set. The book doesn't elaborate on this, however. I don't understand why a Polynomial Ring couldn't have an inverse multiplicative for every element (at least in the Whole numbers, and it's already given that it has a neutral element). Could somebody please explain why this can't be so? |
I've recently installed Ubuntu 12.04 it was working fine unless I messed up with a command. I change all user permissions(as they call ago permission in Ubuntu) by running command sudo chmod -R 777 /. Now system won't detect any external devices like USB or any internal hard disk,but strangely it detect my mouse and keyboard. And system is also not able to recognize any wired connection. By using chmod I think I messed up with admin privileges and sudo command won't work.Is there Any other solution other than re-installing the whole OS? Can I restore my system in previous mode by any command? | I accidentally executed sudo chmod -R 777 / I was actually trying to change a specific folder permission recursively, btw i did stop the command before it changed everything. But now, i can't execute for example sudo Every time i try to sudo something it throws me this error: effective uid is not 0, is sudo installed setuid root? Btw i know i can use chown -R root:root /usr/bin where sudo is located, but of course i don't have the permissions to do this. So, how can i revert this process? Or at least save the sudo file without reinstalling everything? The system is still connected to the internet and seems to work fine besides the sudo issue. Thanks in advance. |
My friend and I made a minecraft server, and he can connect to many other servers like hypixel and manacube. But for some reason this is the only server he cant connect to. When he tries to join, this error pops up: z: IO.NETTY.CHANNEL.ABSTRACTCHANNEL$ANNOTATEDCONNECTEXCEPTION : CONNECTION REFUSED: NO FURTHER INFORMATION: He has tried: Restarting Minecraft Restarting the computer Uninstalling and reinstalling Minecraft Uninstalling and reinstalling Java Altering firewall Restarting Internet I've messed with my port, made a second Windows account, reset netsh winsock, and checked hosts. Any recommendations? Also, he can join the server on other WiFi networks. | I am getting the following error when I try to connect to a Minecraft server: This is all servers, not just one. The error says: io.netty.channel.AbstractChannel$AnnotatedConnectException: Connection refused: no further information: Version 1.12 I've tried: Restarting Minecraft Restarting Computer Uninstalling and Reinstalling Mincraft Uninstalling and Reinstalling Java Altering Firewall Restarting Internet I've messed with my port, made a second windows account, reset netsh winsock Checked hosts Made a new WINDOWS account The overlay in the bottom right is Geforce's Overlay for game capturing. I don't have any mods installed. A Mojang support ticket wouldn't help. Im desperate. |
The following example gives: ! Package array Error: Illegal pream-token (\AtEndOfPackage): `c' used. What is wrong? \documentclass{article} \usepackage{tabularx} \newenvironment{mytab}{ \begin{tabularx}{5cm}{l} }{ \end{tabularx} } \begin{document} \begin{mytab} foo \\ bar \end{mytab} \end{document} | There's something wrong with this code: \newenvironment{Tbl} {\begin{tabularx}{\textwidth}{|l|X|} \hline} {\end{tabularx}} but this is fine: \newenvironment{Tbl} {\begin{tabular}{|l|l|} \hline} {\end{tabular}} Why? And how can I get the first to work? Here is the full LaTeX file: \documentclass[a4paper, 12pt]{article} \usepackage{tabularx} \newenvironment{Tbl} {\begin{tabularx}{\textwidth}{|l|X|} \hline} {\end{tabularx}} \begin{document} \begin{Tbl} \end{Tbl} \end{document} latex test.tex produces: This is pdfTeXk, Version 3.141592-1.40.3 (Web2C 7.5.6) %&-line parsing enabled. entering extended mode (./test.tex LaTeX2e <2005/12/01> Babel <v3.8h> and hyphenation patterns for english, usenglishmax, dumylang, noh yphenation, arabic, basque, bulgarian, coptic, welsh, czech, slovak, german, ng erman, danish, esperanto, spanish, catalan, galician, estonian, farsi, finnish, french, greek, monogreek, ancientgreek, croatian, hungarian, interlingua, ibyc us, indonesian, icelandic, italian, latin, mongolian, dutch, norsk, polish, por tuguese, pinyin, romanian, russian, slovenian, uppersorbian, serbian, swedish, turkish, ukenglish, ukrainian, loaded. (/usr/share/texmf/tex/latex/base/article.cls Document Class: article 2005/09/16 v1.4f Standard LaTeX document class (/usr/share/texmf/tex/latex/base/size12.clo)) (/usr/share/texmf/tex/latex/tools/tabularx.sty (/usr/share/texmf/tex/latex/tools/array.sty)) (./test.aux)) Runaway argument? \par ! File ended while scanning use of \TX@get@body. <inserted text> \par <*> test.tex ? |
plz I want your help with java program this program ask user to enter (day,month,year) of current day and give him the next day (day,month year ) . for example : enter the day: 28 enter the month: 2 enter the year: 2014 the next day is: 1/3/2014 | I'm working with a date in this format: yyyy-mm-dd. How can I increment this date by one day? |
Trying install the on my Ubuntu. When running ./install.sh bash: ./install.sh: /bin/bash^M: bad interpreter: No such file or directory it throws the error. I then cd into that folder and found the bash folder is there. how to fix it? | I wanted to execute a shell script: -rwxr-x--x 1 root root 17234 Jun 6 18:31 create_mgw_3shelf_6xIPNI1P.sh I tried to do a standard procedure, but I got this error: ./create_mgw_3shelf_6xIPNI1P.sh localhost 389 -l /opt/fews/sessions/AMGWM19/log/2013-06-06-143637_CLA-0 DEBUG cd/etc/opt/ldapfiles/ldif_in ; ./create_mgw_3shelf_6xIPNI1P.sh localhost 389 -l /opt/fews/sessions/AMGWM19/log/2013-06-06-143637_CLA-0 **ERROR sh: ./create_mgw_3shelf_6xIPNI1P.sh: /bin/bash^M: bad interpreter: No such file or directory** What does it mean? I was doing this as the root user under the root group. Does it mean that the file does not have the correct permission for the root user? |
I have to design a board with a package case called MSOP-16 It has a large ground pad underneath the IC. What are good methods for soldering this pad by hand with a soldering iron? Since it is a prototype, I was thinking to put a large enough via inside of the pad and to heat the via and drop solder through it from the other side after the outer pins have already been soldered. | I am attempting to make a board for the 24-channel led driver to drive an 8x8 rgb led array. I have made what I think is a good eagle library for the sop-38 package, but I am not sure what to do about the pad on the underside of the ic. The datasheet has thermal characteristics with and without the pad soldered, but I suspect I will want the heat dissipation provided by the pad. This is my most ambitious soldering project yet, and I have a few questions I would like to straighten out before I have the first round of boards made. Should I hook the heatsink to my ground polygon on the bottom side, or leave it disconnected? I'm not sure if it will cause problems with grounding if it heats up too much. Is my only option to reflow this, or is there a way to do it by hand? I have never done any reflow soldering, and I am much more comfortable hand soldering. I am definitely not comfortable having a stencil made to do this kind of thing. Is there any kind of thermal compound or something that can make a thermal connection comparable to a solder joint, or is solder best? The datasheet has very specific dimensions for pad size, via patterns, and stencil opening. Should my solder mask pretty much follow the stencil opening outline on the datasheet? |
When you do a Twitter onebox, it embeds the twitter text nicely. However, if the tweet is mostly for the sake of sharing an image, that text isn't really useful, and you then need to click the link in the tweet to view the image. This kinda undermines the point of oneboxing. Can embedded images get added to Twitter oneboxes? | Some sites are . What additional sites should the chat support? One suggestion per answer. |
How does a cracker know if they've broken CBC or stream encryption? With hashe cracking one would know because you have the password that you started with to test. But for CBC decryption, you have a 16 bit block (AES), a key, and an IV. With the wrong key one will get random data as output. So how will one know when the right key was found? The output may be binary so how is it determined if the decryption was a success? Does the attacker require knowledge of the type of contents, to search for magic numbers or headers? | Given a CBC ciphertext and IV, how can I find the encryption key? We are limited with an 8 chars key, each char in the range of [a..h], so I can generate every possible key (these are only $8^8 = 2^{24}$ (about 4 million) different possible keys). How would I go about finding the correct one though? |
I want a formula that highlight the dates that within next week. I know how to highlight within the current week, with this formula: =TODAY()-WEEKDAY(TODAY(),3)=$F6-WEEKDAY($F6,3) (shown in the red highlight) and I also know how to highlight within the 7 days after 7 days from today, with this formula: =AND($F6-TODAY()>=7,$F6-TODAY()<=13) (shown in the green highlight) but what about highlighting all dates within next week, regardless being synchronous with today? Notice that the green highlight does not cover next Monday as the 7 days are formulated to move synchronously with today date not limited to be within next week. | I am trying to format cells in Excel 2013. I want the cells to get colored as green, yellow, and red based on how close they are with the target date (January 13, 2015 in this case). I am unable to use conditional formatting as Excel says that relative formatting is not permitted within conditional formatting. Target: 06-01-2015 01-01-2015 02-01-2015 03-01-2015 04-01-2015 05-01-2015 06-01-2015 07-01-2015 08-01-2015 09-01-2015 10-01-2015 If the date in the cell is more than 2 days of the target date, I want the cell to change color to Green. I used =DATEDIF($N12,$N$9,"d")>=3 and the format changed to green. If the date in the cell is exactly 2 days near the target date, I want the cell to change color to yellow. I used =DATEDIF($N12,$N$9,"d")=2 and the format changed to yellow. If the date in the cell is within 2 days of the target date, I want the cell to change color to red. I used =DATEDIF($N12,$N$9,"d")<2 and the format changed to red only for 5th and 6th January. Apparently, it does not recognize negative values. How can I get this to match the required colors? |
My goal is to calculate the integral $\int_{0}^{\infty} x^{a-1} \cos(x) dx = \Gamma(a) \cos (\pi a/2)$, where $0<a<1$, and my textbook provides the hint: integrate $z^{a-1} e^{iz}$ around the boundary of a quarter disk. However, I couldn't figure out how to control the integral over the quarter arc. Any hints? | I need to prove $\int_{0}^{\infty}\cos(t) t^{z-1}dt=\Gamma(z)\cos(\frac{\pi z}{2})$ for $0<Re(z)<1$. I tried $\cos t=\frac{e^{it}+e^{-it}}{2}$ and to integrate it along the contour from $\epsilon $ to R, then to $Ri$ via a quarter of a circle, then downward to $\epsilon i$, finally back to $\epsilon$ via a small quarter of a circle. However, I find that $e^{-it}t^{z-1} $ does not converge when $R\to \infty$, can anyone give a correction of my integration or offer another method to evaluate the integral?(would be better if using complex contours) thanks in advance. |
Fluffy's chamber on the third floor didn't have any special lock. It could easily be unlocked using Alohomora. Alohomora was a basic spell which even first years could use and that's how our heroes got into the Fluffy's chamber. Instead of instructing students to not go into forbidden area on third floor, why wasn't the door simply locked with anti-Alohomora charm? It could also keep the thieves away. Talking about feasibility of anti-Alohomora charm, in the quest to Philosopher's Stone, the trio found Alohomora not working on a door whose key was flying around. It means that doors can be locked in such way that Alohomora couldn't work. Why wasn't the first door locked such way? Dumbledore himself could carry its key in his pocket. | In the Harry Potter universe, there is a spell that unlocks things. In the books and movies, there are many occasions where the main characters use this spell to open doors in wizard buildings (such as the door leading to where the Philosopher's Stone is hidden, or a door in the Magical Congress Of USA headquarters). Hermione knows the spell in her first year, which seems to indicate it's pretty easy to learn/cast, especially for the average adult wizard. What I'm wondering, then, is why do wizards lock their doors when it's so easy to unlock them? And if it's so easy to unlock locked doors, why aren't there more doors locked with enchantments? |
I last visited any Stack Exchange sites a couple of weeks ago. This morning, I was not automatically logged in to any site, and had to log in manually. I could not recall my password and had to reset it. Subsequently, each site automatically recognises my login, welcomes me back, but then refreshes me automatically back to the page I was previously on without actually logging me in. The issue does not occur using Chrome as a browser - that is how I am posting this. | Here's what is happening; everytime I go to Stack Overflow (stackoverflow.com, NOT meta) with Firefox, it gives me the "Welcome back" tab that pops up from the top. Whenever I click in the "click here to refresh the page" link, all it does is refresh the page without logging me back in. Even if I try to log in using the "log in" button at the top, all it does is pop up the tab that says "Welcome name here, you're being redirected." The problem is I'm not being logged in, not to mention that it keeps refreshing the page over and over again without giving me a choice to log in with Facebook. For some reason, I was capable of logging in to Meta Stack Overflow using Firefox. I am still unable to log in to Stack Overflow. Any ideas? |
I'm trying to reverse and return a StringBuilder result but I get the following errors for trying all variations in order of return sb.Reverse().ToString(): Cannot implicitly convert type 'System.Collections.Generic.IEnumerable' to 'string'. 'StringBuilder' does not contain a definition for 'Reverse' and no extension method 'Reverse' accepting a first argument of type 'StringBuilder' could be found What is the proper format for returning the stringbuilder result in reverse order? public static string Reverse( string s ) { char[] charArray = s.ToCharArray(); Array.Reverse( charArray ); return new string( charArray ); } This bit of code unfortunately doesn't do it one line Please vote to delete this post so I can get rep back XD | I've just had to write a string reverse function in C# 2.0 (i.e. LINQ not available) and came up with this: public string Reverse(string text) { char[] cArray = text.ToCharArray(); string reverse = String.Empty; for (int i = cArray.Length - 1; i > -1; i--) { reverse += cArray[i]; } return reverse; } Personally I'm not crazy about the function and am convinced that there's a better way to do it. Is there? |
*nix commands (and functions?) have a number with them, like fsck(8), killall(1), etc. What does the number mean? | So, for example, when I type man ls I see LS(1). But if I type man apachectl I see APACHECTL(8) and if I type man cd I end up with cd(n). I'm wondering what the significance of the numbers in the parentheses are, if they have any. |
I'm using ubuntu 14.04 LTS 32 bit OS. Please anyone can tell me how to add background image for nautilus(file browser) and change the background color of nautilus. Please help me. | As the question goes, How can I change the background of nautilus in Ubuntu 14.04 ?? I have already tried dconf-editor, gtk-tweaker, gnome-tweaker. They change the color of some parts of some pannel but not the background of nautilus in icons view. |
In my scene there are some objects that are somehow connected to each other. E.g. if I transpose one object called 'Body' it also moves the object 'Border'. The movement of 'Border' is not linear to 'Body'. I removed all groups, constraints, parenting etc. of all objects. So I can not see any relationship between the objects. Any ideas? | I'm facing this frustrating "feature" that I can't seem to remedy; when I duplicate an object (and now, even when I create two completely new objects), their transformations/scaling is synchronized. This is extremely annoying when trying to use any sort of transformation keyboard shortcut. It should be noted by going to the properties menu (N) and manually setting the properties works just fine. For instance, here is just the camera selected (trust me, I made sure): And when I try to transform by clicking+dragging on the X axis OR by hitting G->X, this happens: They are not grouped (verified by going to the Groups list up in the Scene panel) and they do not have parents (verified by going to Object->Relations). I have tried the unlink command as well, to no avail. I have seriously run out of options; what did I change to have my G->X shortcuts transform multiple objects? It seems completely at random, too; certain objects seemed to be "linked" to other random objects, and this "linking" is guaranteed when duplicating even when I do a non-linking duplicate (Shift+D). What gives? |
If we consider two implementations below, what's the actual use of the first one? List<String> a= new ArrayList<String>(); ArrayList<String> b= new ArrayList<String>(); From what I have read in the posts, the first implementation helps in avoiding breaking change like we can change the implementation again as a=new TreeList<String>(); But I don't understand whats the actual use of changing the implementation with treelist as we can use only the List interface methods? | I have seen this mentioned a few times and I am not clear on what it means. When and why would you do this? I know what interfaces do, but the fact I am not clear on this makes me think I am missing out on using them correctly. Is it just so if you were to do: IInterface classRef = new ObjectWhatever() You could use any class that implements IInterface? When would you need to do that? The only thing I can think of is if you have a method and you are unsure of what object will be passed except for it implementing IInterface. I cannot think how often you would need to do that. Also, how could you write a method that takes in an object that implements an interface? Is that possible? |
When I was measuring the current with varying frequency of an series RLC circuit, I noticed that the graph produced is asymmetric: Is there any reason for this? (inductance=8.29mH) The Q-factor is 2.75 (3 s.f.) | I understand that in a Frequency Response experiment dealing with an RLC circuit, the graph of Current against Frequency is supposed to be symmetrical about the resonant frequency theoretically. However, experimentally it is not the case. Could anyone explain why this happens? |
I am trying to understand what the bellow statement means. if [ ! -n "$1" ] What I understand from the rest of the statement is: An if statement (if), something I do not understand ( ! ), checks the length of a string is nonzero ( -n ), the first argument ( "$1" ) | Consider the following in bash: root@debian-lap:/tmp I=$(echo) root@debian-lap:/tmp echo "$I" root@debian-lap:/tmp [ -z "$I" ] && echo "TRUE" || echo "FALSE" TRUE This means that variable $I is zero. The same I could achieve with negation test to see if variable is non zero, and ! makes test reverse so it checks is variable zero root@debian-lap:/tmp ! [ -n "$I" ] && echo "TRUE" || echo "FALSE" TRUE root@debian-lap:/tmp So, my question is, are there any special cases when to use -z and ! -n , or vice versa ! -z and -n as they are basically doing the same test? Thanks |
In main page index.php I have two href (like menu) for objective.php and news.php For both objectives and news I sent variables like: <a href="objectives.php?menu=corporate-objectives"> <a href="news.php?article=meetings"> The idea is to load content for each page separately and to change the url's to symbolic links like: /MyTest_proj/corporate-objectives /MyTest_proj/meetings I've tried in many ways to rewrite rules in htaccess especially to rewriterule for both pages but most of time work only for the first rewriterule for example: RewriteRule ^([-a-zA-Z0-9]+)?$ objectives.php?menu=$1 RewriteRule ^([-a-zA-Z0-9]+)?$ news.php?article=$1 which obviously both page match the same paterns and the meetings was loaded in objectives.php otherwise (or in other case) I got the 401 error... The question is how do I must put and to write these rewriterules and conditions if there is any to work for both pages ? | This is a about Apache's mod_rewrite. Changing a request URL or redirecting users to a different URL than the one they originally requested is done using mod_rewrite. This includes such things as: Changing HTTP to HTTPS (or the other way around) Changing a request to a page which no longer exist to a new replacement. Modifying a URL format (such as ?id=3433 to /id/3433 ) Presenting a different page based on the browser, based on the referrer, based on anything possible under the moon and sun. Anything you want to mess around with URL Everything You Ever Wanted to Know about Mod_Rewrite Rules but Were Afraid to Ask! How can I become an expert at writing mod_rewrite rules? What is the fundamental format and structure of mod_rewrite rules? What form/flavor of regular expressions do I need to have a solid grasp of? What are the most common mistakes/pitfalls when writing rewrite rules? What is a good method for testing and verifying mod_rewrite rules? Are there SEO or performance implications of mod_rewrite rules I should be aware of? Are there common situations where mod_rewrite might seem like the right tool for the job but isn't? What are some common examples? A place to test your rules The web site is a great place to play around with your rules and test them. It even shows the debug output so you can see what matched and what did not. |
I understand what they both are, but how exactly is something "made" to be edge triggered? I understand some computer architecture concepts, and while I understand individual components (gates/flip flops/etc...) I don't understand what makes something rising edge/falling edge triggered or level triggered for example? Im more or less looking for a "Physical" reason that determines why one vs the other. | I am studying 8085 microprocessor architecture and the word edge triggered and level triggered confusing me really very much. Can anyone explain me it in layman's words ? While studying the interrupts of 8085 named RST 7.5, RST 6.5, RST 5.5 and TRAP i came across these words and they confused me. Here i have attached one document link from which i was reading and i have mentioned my confusion diagrams. in the document RST 7.5 -> Edge triggered RST 5.5 -> Level triggered. TRAP -> Edge triggered and Level triggered. (why ? does it make any difference?). |
Iam using a php web site which ia by default has iso-8859-1 header type in html page. I had changed it to utf-8 then the special characters were showing in different way [ not rendering properly] Edit: Header: <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> echoing the string which is showing as mentioned below: 1. Nytt filter f�r v�lja spr�k och aktiva Medarbetare May i know the reason. Thanks | I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1. Where exactly do I need to set the encoding/charsets? I'm aware that I need to configure Apache, MySQL, and PHP to do this — is there some standard checklist I can follow, or perhaps troubleshoot where the mismatches occur? This is for a new Linux server, running MySQL 5, PHP, 5 and Apache 2. |
There used to be other sports like where they used to have an offside rule. To continue with the example of field hockey, the games were too defensive, and they weren't that many goals (which makes a sport less attractive to watch). To prevent this, they abolished the offside rule (which was similar to the one in association football if I'm not mistaken). The results of this abolishment was that the sport became more offensive, there were much more goals and at the end it became more popular because of this. Why doesn't FIFA abolish this rule? Games where there are a lot of goals are the best ones to watch and would make the sport more popular in the US for instance. Even more, the offside rule is often the most contested one and the most difficult to spot correctly. | The offside rule in football ( ) is the source of a large amount of goal-related controvesy, and is argued by some to diminish the entertainment value of the game. It is also argued that since its abolition from Hockey, that game has become more entertaining. Periodically, plans are mooted, but invariably fail. So, what are its origins, and why have all calls to scrap it been resisted? |
Does the following PHP MySQL statement protect against SQL Injection? $strSQL = "SELECT * FROM Benutzer WHERE Benutzername = '".$Benutzer."' AND Password = '".md5($PW)."'"; The Variables $Benutzer and $PW are inputs from the User. We're checking the username and password against common SQL Injection techniques: ' or 0=0 --, " or 0=0 --, or 0=0 --, ' or 0=0 #, " or 0=0 #, or 0=0 #, ' or 'x'='x, " or "x"="x, ') or ('x'='x, ' or 1=1--, " or 1=1--, or 1=1--, ' or a=a--, " or "a"="a, ') or ('a'='a, ") or ("a"="a, hi" or "a"="a, hi" or 1=1 --, hi' or 1=1 --, hi' or 'a'='a, hi') or ('a'='a and hi") or ("a"="a. Am I missing something? Should I use a different method to protect against SQL injection? | If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example: $unsafe_variable = $_POST['user_input']; mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')"); That's because the user can input something like value'); DROP TABLE table;--, and the query becomes: INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--') What can be done to prevent this from happening? |
The chinese website said : In the most of atom,the number of neutron higher than the number of proton Does anyone know the reason?just explain it in easier way, Or does anyone know if the number of neutron be less than the number of proton,what will happen with atom?why? | While studying the semi-empirical mass formula for nuclei, I came across an "asymmetry term" whose function, as far as I understand, is to build in the fact that nuclei "prefer" to have equal numbers of protons and neutrons. This is explained by the Pauli exclusion principle; the neutrons and protons are distinguishable, and hence have fill separate energy levels. Hence, if the number of neutrons and protons is close, the nuclei will have a smaller energy. Yet, it is observed that large stable nuclei have more neutrons than protons. Why is this so? If nuclei prefer to have equal protons and neutrons, shouldn't the stable nuclei lie along the N=Z line? (in the image) |
Recently, when I tried to encrypt a folder in my external HDD, I was presented with a dialogue box as given below: What' the difference between Apply changes to this folder only and Apply changes to this folder, subfolders and files in encrypting a folder? If I select the first one, will the folder be accessible to others(and the files inside it)? UPDATE: answers my question partially, but not the second part about the accessibility of the files inside that folder. | I'm familiar with bitlocker, having been using it for a while, but I am looking at just encrypting a folder instead. But I just don't understand the options it's giving me. When I right-click a folder > properties > advanced > [x] encrypt contents to secure data > OK < apply > ... I get: () apply changes to this folder () apply changes to this folder, sub-folder and files. This doesn't make sense to me at all, if I encrypt a folder then the whole folder, everything within it is encrypted, then why should I be given these options, how can I have a folder encrypted and files within that folder unencrypted, that seems stupid to me, it doesn't make sense at all. Can anybody explain why these options exist and how can I simply encrypt a folder? |
Consider 9 random and distinct real numbers. Prove that there exist at least 2 of them, $m$ and $n$, for which $0 < \frac{m-n}{1+mn} < \sqrt{2}-1$. Any ideas? I really don't know where to start from! The friend who challenged me with this problem claims that it can be solved by using pigeonhole principle, but I have no idea how!! | For any given set of 13 distinct real numbers, prove we can always find two numbers x and y that $0<\dfrac{x-y}{1+xy}\leq 2-\sqrt{3}$. I knew we can always make $0<\dfrac{x-y}{1+xy}$ happen. Since x and y are distinct, we can just switch the order of x and y to change the sign of $\dfrac{x-y}{1+xy}$, but what should I do for the right hand side? |
Can I remote into Windows 7 as one user, while another user is logged in at the computer as a different user - and have both be able to do stuff at once? | I have a Windows 7 computer that is acting as a Media Center so it is always on but not always in use. I would like to be able to log in to this machine remotely and launch some scripts that take time to compute. If I use Remote Desktop I can get a view of the desktop and use it but the media center view gets blocked (I get the log in screen). If I use LogMeIn, the media center application closes (not compatible with remote use) and the both the remote and media center views are the same. Is there a way to access the computer remotely to launch and monitor these scripts while not disturbing the media center users? |
Problem How many elements are there in $\mathbb{Z}[i]/I$ where $I= \langle2+2i\rangle$ $2+2i + I =I$ . So $2+2i$ is equivalent to $0$ . So $2+2i=0$ which implies $i=-1$ which inturn implies $2=0$. How to move after that? | The question is : Show that $I=\langle 2+2 i\rangle$ is not a prime ideal of $\mathbb Z[i]$. Also find the number of elements in $\mathbb Z[i]/I$ and its characteristic. My try: I started with elements $2, 1+i \in \mathbb Z[i]$. Clearly, the product is $0$ in the coset representation. The part where i am struck at is the number of elements and the characteristic. Well, $2+2i+\langle 2+2i\rangle=0+\langle 2+2i\rangle$ Can we directly write $i^2=-1$ in the coset representation? |
It seems that having a clickable mailto link is a good UX, especially for mobile users. But from what I understand, mailto links open up an email to spam more easily due to spam bots. At least, that's what used to be said about them years ago (today is 2018). The question is, are mailto links still as 'dangerous' as they once were? Is spam / bots something to worry about, or does the good UX of a clickable link outweigh the negative? I tried to find the answer to this but can't seem to find much relevant info in 2018. A few sites like Hubspot talk about using mailto links still, so it seems that maybe mailto is back to being a good option. What do you think? | What's a good way to list a "Contact Us" email address on a web site, while reducing the likelihood it will get spammed? Is putting the email address in an image the best technique, or are there others? |
When creating this question, StackExchange told me that this question appears subjective and is likely to be closed, but I'm going to ask it anyway to see if anyone can help me answer this. Sorry if this is not a valid question for Math StackExchange In previous courses (and looking online) the method I've always been taught to find a confidence interval with $c\%$ for $\mu_1 - \mu_2$ when both $\sigma_1$ and $\sigma_2$ are unknown is $$(\bar{x}_1 - \bar{x}_2) \pm t_c \sqrt{\frac{s^2_p}{n_1}+\frac{s^2_p}{n_2}} $$ With degrees of freedom $n_1+n_2-2$ and $s^2_p = \frac{(n_1-1)(s^2_1)+(n_2-1)(s^2_2)}{n_1+n_2-2}$ However in my class this year my professor told me that the formula is: $$(\bar{x}_1 - \bar{x}_2) \pm t_c \sqrt{\frac{s^2_1}{n_1}+\frac{s^2_2}{n_2}} $$ With degrees of freedom being the smaller of $n_1-1$ and $n_2-1$ My question is this: Are these two formulas interchangeable? Or is one better than the other? Thank you. | I mostly see this formula when searching for a formula for the estimate of the standard error in difference between two means, and it is also used in . $$\Delta=\sqrt{s_1^2/N_1+s_2^2/N_2}$$ But I've also seen this one (and this is the one my book uses): $$\Delta'=\sqrt{\dfrac{\left(N_1-1\right)s_1^2+\left(N_2-1\right)s_2^2}{N_1+N_2-2}\left(\dfrac{1}{N_1}+\dfrac{1}{N_2}\right)}$$ As these are two very different formulas, how come they are used seemingly interchangeably? |
I'm in Southern Germany and just captured this animal crawling along my wall at considerable speed, apparently hiding from the light. It looks like a entipede from afar (about two dozen legs), and closer inspection reveals it has long legs, a clearly visible head, two long feelers, and striped hind legs. It's about 3-4 cm (1.5in) in length if I recall correctly. Below are the best-quality photos I managed to take before setting it free outside. I'm as ignorant about arthropods as I am averse to them, and I'd very much like to know if this one is harmful or not, and whether to expect more of those around the house. | I found the insect nside house near Shirdi, Maharashtra. I have captured the image |
Edo Tensei restores a person the way they were at the time of their death. When Madara died, he was wrinkly and old. How come Edo Tensei Madara is brand new? Rinnegan is not a kekkei genkai/tota. Why does Edo Tensei Madara still possess the Rinnegan when, at the time of his death, he wasn't possessing Rinnegan (because he implanted them onto Nagato)? Madara lost vision in one eye due to usage of Izanagi, but after awakening the Rinnegan, was he able to restore his Eternal Mangekyou Sharingan that he lost? | Madara gave his Rinnegan to Nagato. But after Kabuto brings him back using Edo Tensei, he still has the Rinnegan. How is this possible? |
There are words that have "j" where in most languages it would be pronounced like romaji "y". Take for example "Jesus", "Jehovah", "John". It should be pronounced "Yesus", "Yehovah", "Yohn". Slavic languages and Esperanto have "j" sound like romaji "y" so if you'd write "Jessica", it would be pronounced "Yessica". Now, why isn't that in English? Why does also in Spanish "j" sound like "h"? How did this transformation start? Also, why is "halelujah" not written like it's pronounced: "haleluyah"? Ironically "trojan" is not just an English word, but a Croatian word too that sounds like "troyan". Why is the "j" there if it sounds like "g" and not "y"? Why isn't "Troy" "troj"? I'm so confused! When is it "j" and when is it "y"!? | I understand that the letter "J" is relatively new — perhaps 400–500 years old. But since there has long been important names that begin with J, such as Jesus, Joshua, Justinian, etc., and which predate the introduction of a special letter, does that mean that the "J" sound predated the letter, or were such famous names spelled and pronounced differently? |
I did as per the solution given in But when I check nodejs --version I get v8.10.0 And when I install using this command sudo n latest I get installed : v13.8.0 (with npm 6.13.6) I have the same version problems with node and npm too, the latest verion installed is not reflected. whereis nodejs I am getting this output: nodejs: /usr/bin/nodejs /usr/lib/nodejs /usr/share/man/man1/nodejs.1.gz I tried uninstalling nodejs and installing again the same thing happens. Is this a problem with ubuntu? | I noticed over at the website that node is currently at v 0.12.0. Can someone let me know how to install the latest version of node together with npm (terminal commands please)? |
I have the following shell script in order to connect to database and do some tasks. echo Please enter userid: read USER_NAME echo "Please enter password:" read -s PASS SID=${ORACLE_SID} if [ "${ORACLE_SID}" != 'TEST' ] then sqlplus -s -l $USER_NAME/$PASS@$SID << EOF copy from scott/tiger@orcl insert emp using select * from emp exit EOF else echo "Cannot copy" fi However 1when I execute I am getting errors Please enter local Username: scott ': not a valid identifierd: `USER_NAME copy_data.sh: line 3: $'\r': command not found Please enter local Password: ': not a valid identifierd: ` copy_data.sh: line 6: $'\r': command not found copy_data.sh: line 8: $'\r': command not found copy_data.sh: line 18: syntax error near unexpected token `fi' copy_data.sh: line 18: `fi' How can I resolve this issue Debug mode $ bash -x test.sh + echo 'please enter username' please enter username + read user_name vbx + echo 'please enter password' please enter password + read -s pass + echo test.sh: line 12: syntax error near unexpected token `else' test.sh: line 12: `else' | I'm on windows 7 using Cygwin. My script and text file are located in the same directory. #!/bin/bash while read name; do echo "Name read from file - $name" done < /home/Matt/servers.txt I get this error and I don't know why because this is correct while loop syntax..? u0146121@U0146121-TPD-A ~/Matt $ ./script.sh ./script.sh: line 4: syntax error near unexpected token `done' ./script.sh: line 4: `done < /home/Matt/servers.txt' Can anybody tell me what I'm doing wrong? I think its because I'm on windows and using Cygwin. |
Simple question: Most power supplies are auto-sensing between 110V/120V and 220V/240V. This begs the question, can they use 240V in North America i.e. connected to both hots (red and black)? | Simple question: Most computer power supplies are auto-sensing between 110V/120V and 220V/240V. This begs the question, can they use 240V in North America i.e. connected to both hots (red and black)? |
Assume that I have some subclasses that extend a superclass. These subclasses differ by the parameters passed to the superclass. Unfortunately, like the following example, I can end up with "many" parameters. Is there a general method of avoiding this? Are constructors with "many" arguments considered good practice? Would it be better to have getter/setter methods instead of passing every parameter via constructor? public abstract class SuperClass { private int a; private int b; . . private int z; public SuperClass(int a, int b, ... int z) { this.a = a; this.b = b; . . this.z = z; } } public class SubClass1 extends SuperClass { public SubClass1() { super(4, 3, ..., 9); } } public class SubClass2 extends SuperClass { public SubClass2() { super(1, 7, ..., 2); } } | In some of our projects, there's an class hierarchy that adds more parameters as it goes down the chain. At the bottom, some of the classes can have up to 30 parameters, 28 of which are just being passed into the super constructor. I'll acknowledge that using automated DI through something like Guice would be nice, but because of some technical reasons, these specific projects are constrained to Java. A convention of organizing the arguments alphabetically by type doesn't work because if a type is refactored (the Circle you were passing in for argument 2 is now a Shape) it can suddenly be out of order. This question might be to specific and fraught with "If that's your problem, you're doing it wrong at a design level" criticisms, but I'm just looking for any viewpoints. |
English grammar has been confusing me for a long time, so I want to ask some questions about the past and how you use it. I'm more interested in information about British English. When and how do you use, for example: haven't felt, hadn't felt, felt, wasn't feeling, has been feeling, used to feel. and what's the difference between them? I kind of understand the difference, but not sure if I do it correctly. | Non-native speakers often get confused about what the various tenses and aspects mean in English. With input from some of the folk here I've put together a diagram that I hope will provide some clarity on the matter. I offer it as the first answer to this question. Consider it a living document. Input is welcome, and good suggestions will be incorporated into the diagram. Nota bene: What this is not is a discussion of whether there are more than two tenses in English. , to which this question is not intended to supply arguments one way or the other. Here, the aim is to provide an overview of what constructions English-speaking people use for conveying information about actions referring to past, present, and future, and to provide it first and foremost to precisely the people who are likely to use "tense" as a catch-all term in their search, rather than to linguists who know better. Breaking News There is now an excellent ELU blog article titled . It is highly recommended reading. |
In Zend Framework (1.10) i want to check if two input fields are identical I have the following code in my form: $this->addElement('password', 'password', array( 'label' => 'Wachtwoord:', 'required' => true ) ); $this->addElement('password', 'verifypassword', array( 'label' => 'Bevestig wachtwoord:', 'required' => true, ) ); I already tryed the "identical" validator, but I did'nt got it to work. | I have created a form to add a user to a database and make user available for login. Now I have two password fields (the second is for validation of the first). How can I add a validator for this kind of validation to zend_form? This is my code for the two password fields: $password = new Zend_Form_Element_Password('password', array( 'validators'=> array( 'Alnum', array('StringLength', array(6,20)) ), 'filters' => array('StringTrim'), 'label' => 'Wachtwoord:' )); $password->addFilter(new Ivo_Filters_Sha1Filter()); $password2 = new Zend_Form_Element_Password('password', array( 'validators'=> array( 'Alnum', array('StringLength', array(6,20)) ), 'filters' => array('StringTrim'), 'required' => true, 'label' => 'Wachtwoord:' )); $password2->addFilter(new Ivo_Filters_Sha1Filter()); |
Like 98% of the time I open a Terminal or Nautilus, I want to use it snapped to the right/left... especially if I am using more than one instance of them. Can I configure my Ubuntu to open any instance of Nautilus or Terminal in 'snapped' mode? I am using Ubuntu 15.10. | I'm wondering is there any way to achieve the affect of the Ctrl-Alt-Keypad shortcuts in Unity using terminal commands instead? I want a command that sets a gui window to half the size of the screen, either left or right aligned. By way of background, I'm writing a script that runs after log in. It uses Zenity to ask whether or not I want to open my development environment (GVim and IPython side-by-side). I have been trying to achieve two equal-sized windows for these programmes by using set lines= columns= in my .gvimrc and c.IPythonWidget.width = and c.IPythonWidget.height = in my ipython_qtconsole_config.py. However, there are problems associated with this approach. |
The ACM license states (iii) Post the Accepted Version of the Work on (1) the Author's home page, (2) the Owner's institutional repository, (3) any repository legally mandated by an agency funding the research on which the Work is based, and (4) any non-commercial repository or aggregation that does not duplicate ACM tables of contents, i.e., whose patterns of links do not substantially duplicate an ACM-copyrighted volume or issue. Non-commercial repositories are here understood as repositories owned by non-profit organizations that do not charge a fee for accessing deposited articles and that do not sell advertising or otherwise profit from serving articles. Does this (somehow) include ResearchGate? | I recently created a profile on . And to add your publications list it requires you to upload the paper. Is it legal to upload published journal articles on public servers, where everyone can download it for free? |
I have a branch on GitHub (origin) called issue75. I have a local issue75 branch that I'm trying to sync up with origin, but when I run the following... git merge origin/issue75 I end up with a message telling me "Already up-to-date." However, if I compare them with... git diff origin/issue75 I do see that there are differences between the files in my local issue75 branch vs. the origin/issue75 branch. I'm not sure how to resolve this at this point and would appreciate any assistance I can get. Thanks! | I have a git repository with 2 branches: master and test. There are differences between master and test branches. Both branches have all changes committed. If I do: git checkout master git diff test A screen full of changes appears showing the differences. I want to merge the changes in the test branch and so do: git merge test But get the message "Already up-to-date" However, examining files under each different branch clearly shows differences. What's the problem here and how do I resolve it? |
Can anyone prove this using only linear combination/matrix multiplication ? Let $A$ and $B$ be $2 X 2$ matrices such that $AB = I$. Prove that $BA = I.$ $\left[\begin{matrix} a&b\\c&d \end{matrix}\right]\left[\begin{matrix} e&f\\g&h \end{matrix}\right]=\left[\begin{matrix} 1&0\\0&1 \end{matrix}\right]$ is of no use as I end up with so many unknowns $AB=\left[\begin{matrix} A_{first row}B_{first column}&A_{first row}B_{second column}\\A_{second row}B_{first column}&A_{second row}B_{second column} \end{matrix}\right]$ is also not helping | If $A$ and $B$ are square matrices such that $AB = I$, where $I$ is the identity matrix, show that $BA = I$. I do not understand anything more than the following. Elementary row operations. Linear dependence. Row reduced forms and their relations with the original matrix. If the entries of the matrix are not from a mathematical structure which supports commutativity, what can we say about this problem? P.S.: Please avoid using the transpose and/or inverse of a matrix. |
I have 60 Sheets with the same information but for different employees. I was wanting to create a summary sheet but without manually linking. In the summary sheet, I want cell A6 from each sheet to appear in cells B1:B60. I tried entering 1 through 60 in cells A1:A60 and then using =CONCATENATE("Sheet",A1,"!A6") so that I could drag it down easily but it just returns Sheet1!A6. Any ideas? Thanks | I have text in a cell (A1) that is also the name of a worksheet within my workbook. How do I go about referencing a specific cell on that sheet? I want it to look like the formula below without having to type in the text manually. ='Tab Name'!D16 |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.