Software for graphing equations from user input

[u_know_who]

Hi, I am a new member here. Find this forum very interesting. I don't find any request zone. So i am posting here. Forgive me if any mistakes.
However, i need a software which will give me the graph of the given equation. That means i will enter an equation and it will show me its graph. Can anyone help me?

 

[CRGreathouse]

http://pari.math.u-bordeaux.fr/

 

[fatra2]

gnuplot

Great OpenSource, that has been around for many, many, many years.

Cheers