Function InvRNormalized

* Function: InvRNormalized * * Description: use Newton's method to solve for x = 1/r * * Inputs: r = Q31, range = [0.5, 1) (normalize your inputs to this range) * * Outputs: none * * Return: x = Q29, range ~= [1.0, 2.0] * * Notes: guaranteed to converge and not overflow for any r in [0.5, 1) * * xn+1 = xn - f(xn)/f'(xn) * f(x) = 1/r -