Is there anywhere containing all the standard equations from maths, physics, etc like Pythagoras, Orbital lifetime, etc? I only need the ones that are feasible to compute on a desktop PC without taking more than an hour at most and isn't too specialised.

I don't know if it's possible to find but ideally I would like a function for solving each equation (a, b, c) = fn(x, y, z). Even if implementation isn't available at least the equations would be good.