Is there a good software package for mathematical illustrations?

[Anti Hydrogen]

TL;DR

I'm planning making a guide of calculus so im looking for a software that allows me to make illustrations like they show in the calculus books. do you know any?

Summary: I'm planning making a guide of calculus so I am looking for a software that allows me to make illustrations like they show in the calculus books. do you know any?

thanks in advance

 

[S.G. Janssens]

If you use $\LaTeX$ you may want to look into PGF / TikZ.
(If you do not use $\LaTeX$ you may want to look into that.)

Good luck with your guide!