Macro Library solvers

Some solving algorithms. Version 1.0 Oct 6, 2009

discretenewtons

discretenewtons(function,xmin,xmax,[guess])
applies a discrete form of Newton's method to find a root of the function
on the interval [xmin,xmax]. Starts at midpoint of interval, or at guess if
provided. If method fails to converge, or converges outside interval, the
method returns null. Make sure function uses the variable x