# MATLAB: Trying to do central difference method

central differenceorder of operations

``%QUESTION3 Implements the central differnce method to find the gradient of%y=e^x-2sin^2(2x) at the point where x=1.clear allclcformat longx=1;  % defining xy=1;  % defining y, (y=x)h=0.1  % first value of hx=x+h;  % getting x+h within f(x)y=y-h;  % getting x-h within f(x)  f = @(x) exp(x)-2*(sin(2*x)).^2;  % defining f(x)g = @(y) exp(y)-2*(sin(2*y)).^2;  % defining f(y) to later use as f(x-h)Grad=(f(x)-g(y))/2*h  % Central difference method, Grad = Gradientfor n=1:2  % 2 iterations after h=0.1    h=h/10  % new value for h     x=x+h;  % to replace f(x) with f(x+h)    y=y-h;  % to replace f(x) with f(x-h)    Grad=(f(x)-g(y))/2*h  % Central difference method end``
Here is my code, but my output is incorrect. I did the calculations on paper and they're quite different to my answers. My first value of "Grad" is correct but off by a factor of 1/100. My other two answers are completely wrong.

``6/2*3ans = 9``
``6/(2*3)ans = 1``
``Grad=(f(x)-g(y))/2*h  % Central differnce method, Grad = Gradient``