in pythonfunction is defined using keyword 'defline defines the function with name 'addtwonumwhich takes two parameter and line add the values of 'aand 'band stores the result in variable 'sumfinally line returns the value to function call which is done at line in line function 'addtwonumis called with two values ' and ' which are assigned to variable 'aan 'brespectively in line alsofunction returns the 'sumvariable from line which is stored in variable 'resultsin line (as line called the functionfinallyline prints the result in listing the function is defined with some default valueswhich means if user does not provide all the argumentsvaluesthen default value will be used for the execution of the function listing function with default arguments #funcex pydefault argument can be defined only after non-default argument addtwonum(num = num )is wrong must have some defined value def addtwonum(num num = )return(num +num result addtwonum( print("result =% result result addtwonum( , print("result =% result ''result = result = ''explanation listing function of this listing is same as listing only difference is that the line contains default value for num 'num default value indicates thatif function is called without giving the second value then it will be set to by defaultas shown in line line pass only one value therefore num will be assign whereas num will be assigned default value rest of the the working is same as listing notethere are various other important python features classesdecorators and descriptors etc which are not explained here as we are not going to use these in the coding furtherusing these features we can make code more efficient and reusable along with less error-prone numpyscipy and matplotlib in this sectionwe will use various python librariesi numpyscipy and matplotlibwhich are very useful for scientific computation with numpy librarywe can define array and matrices easily alsoit contains various useful mathematical function random number generator 'randand 'randnetc matplotlib is used for plotting the data in various format some of the function of these libraries are shown in this section furtherscipy library can be used for more advance features complementary error function (erfcand lu factorization etc listing generates the sine wave using numpy librarywhereas the matplotlib library is used for plotting the data listing sine wave using numpy and matplotlibfig numpymatplot py import numpy as np import matplotlib pyplot as plt (continues on next page numpyscipy and matplotlib