There is a button on my calculator dedicated to derivatives and integrals, but I've never been able to use it because I don't know how to represent a variable (it seems the only thing I can derive or integrate with respect to is x, i.e. the operator reads $d/dx$).
As it turns out, there is an "x" button on my calculator, but for whatever reason it seems to represent a constant with the value of 24.8...no idea where that comes from, and using it as normal in a derivative or integral does not work (gives a syntax error).
Here is a picture of my calculator: https://i.stack.imgur.com/8KJU3.jpg
Any ideas at all are appreciated!