I am trying to do some Newton's method-type stuff in Mathematica. I want to build a While loop that does the following: - Take input r. - Compute some quantity f(r). - Update the value of r to f(r). - Repeat until |g(r)| < C for some fixed constant C. The third (boldfaced) step is the one I'm having trouble with. I don't know how to do this. Can someone help?