Define Mathematical Functions in Calc Block

I would love to be able to define my own mathematical functions within the block using the standard notation of f(x) = some function.

Being able to define functions like f(x) = 2x + 1 would save me a lot of time and effort by allowing me to reuse the same functions throughout my work. This would be a valuable addition to the calc block and would benefit many users who work with mathematical expressions on a regular basis.

Would also be great to see the ability to automatically compute derivatives of said functions and/or even plot them similar to demos.