## Newton-Raphson iteration

An iterative algorithm for solving equations. Given an equation,

f x = 0

and an initial approximation, x(0), a better approximation is given by:

x(i+1) = x(i) - f(x(i)) / f'(x(i))

where f'(x) is the first derivative of f, df/dx.

Newton-Raphson iteration is an example of an anytime algorithm in that each approximation is no worse than the previous one.