Newton's method

Etymology
Named after.

Proper noun

 * 1)  A method for finding successively better approximations to the roots (or zeroes) of a real-valued function.

Usage notes
For the equation $$f(x) = 0$$, the iteration is $$x_{n+1} = x_n - \frac{f(x_n)}{f'(x_n)}$$, where $$n = 0, 1, 2, ...$$, and $$x_0$$ is the first approximation to the solution.