Hi, I have bought a Casio FX Cg50.
Is it possible to add programs to calculate for example derivatives? I mean symbolic derivatives and not only the result?
Where can I find programs for this calculator?

Look at chapter 8 here...
http://support.casio.com/storage/en/manual/pdf/EN/004/fx-CG50_Soft_EN.pdf

You might want to check Gbl08ma's Eigenmath port for the Casio Prizm. As far as I remember, the program kind of work on the new model without too much issues, so maybe give it a try!

There are some issues on the new model with it as per following post https://codewalr.us/index.php?topic=1829.msg55803#msg55803 but this addin is hard to compile and if I understand correctly gbl08ma himself had problems recreating the necessary environment to work on it further and left the scene anyway. It is a big loss to prizm community- I like a few of his addins a lot and would not mind continuing their development but I only use Windows and possibly Mac and therefore not able to successfully compile his more complex projects

Thank you for your reply, but is there any kind of guide to install this program?

That's a pity! So there are no programs available yet?

Give it a try and see if the issues are show stopper for you - it may fix itself with new os updates too or you may have other issues- still try and report back