Plot a 50Hz Sine Wave in Excel
This is pretty easy to do:


You need a monotonic time-base. With sin(), you get one complete sine cycle every \$2\pi\$ input values. In this case, I generated a increasing value with a maximum of ~15 (or a bit more then 2 cycles).

Then, you apply the sin() function to the values from the first column, in a second column.

You now have a sine-wave dataset! Plot it:



Volia: A sine wave!

For different frequencies, you can incorporate a scaling value into the time-value before it is fed into the sin() function. This will let you arbitrarily scale the time-units between multiple columns, if needed.


Note that this sine-wave has a peak-peak value of 2 units, and the timebase is arbitrary. I leave scaling the wave up to you (just apply an offset and scaling value to the sinewave column).
I'm assuming familliarity with excel. If you don't know how to plot things in excel, you should ask somewhere like http://superuser.com.
Technically, I did this with LibreOffice. It's close enough.