function fprime = bdiff(f, x, h)
%BDIFF Backward finite difference derivative.
%   FPRIME = BDIFF(F, X, H) computes the derivative FPRIME of the
%   function F at all values in X using a step size of H.
 
fminus = f(x - h);
fx = f(x);
fprime = (fx - fminus) / h;
