Efficient Output Organization for MATLAB Three-Point Derivative Approximation

[Providence88]

So I have this code:

function ApproxSinDeriv(x,n)
h=.5;
for i = 0:n
    h;
    approx = (1/(2*h))*(sin(x+h)-sin(x-h));
    error = abs(approx-cos(x));
    h = h/2;
    A=[i,h,approx,error]
end

Basically, it's a three-point formula for approximating a derivative, where the variables n = the number of iterations, x = the input value for the sin function, i = iteration number, approx=the approximation of the derivative, and error = the difference between the actual derivative and the approximation.

I put A equal to a matrix of these values, but the output comes out in 30 clunky, individual, one-row matrices.

How would I go about putting this data in an array? That is, one nice clean matrix with 30 rows and 4 columns [i,h,approx,error]?

Thanks!

-Eric.

 

[trambolin]

function [A] = ApproxSinDeriv(x,n)
A = zeros(n+1,4)
h=.5;
for i = 0:n
    approx = (1/(2*h))*(sin(x+h)-sin(x-h));
    error = abs(approx-cos(x));
    h = h/2;
    A(i+1,:)=[i,h,approx,error];
end

 

[Providence88]

Thank you! That worked great!