Implementing the derivative in C/C++

Question

How is the derivative of a f(x) typically calculated programmatically to ensure maximum accuracy?

I am implementing the Newton-Raphson method, and it re

Answer 1

Newton_Raphson assumes that you can have two functions f(x) and its derivative f'(x). If you do not have the derivative available as a function and have to estimate the derivative from the original function then you should use another root finding algorithm.

Wikipedia root finding gives several suggestions as would any numerical analysis text.