Solve Any Equation With Newton-Raphson

Suppose you want to solve f(x) = N
Step 1: Compute the derivative d(x)
- Or get the math expert down the hall to do it
Then the answer is:

        sub solve {
          my ($N) = @_;
          my $g = 1;    # Substitute a reasonable guess here
          until (the guess is good enough) {
            $g -= (f($g) - $N) / d($g);
          }
          return $g;
        }

Warnings:
- Initial guess must be reasonable
- Method doesn't always work