# Creating a fourth column of my code

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Hmm! on 16 Jan 2021
I have the following codes:
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format longg
f= @(x) sin(x);
x0 = 2;
ref = cos(2);
hs = 10.^(-(1:16));
errors = [];
for h = hs
derivative = (f(x0+h) - f(x0-h))/(2*h);
error = abs(ref - derivative);
rate = [error(1); error(2:end)./error(1:end-1)];
errors = [errors error] ;
disp([h derivative error rate])
end
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The bolded line is a fouth column in disp([ . ]) which is supposed to be the entries by dividing two consecutive error respectively i,e., the entries in the third column of disp([ . ]). But what I have is rather the repetition of the third column as the fourth column which I dont want. The more I try fixing it, the more difficulties I face. I really need help which is that the fourth column of disp([ . ]) must be the consecutitive division of entries of the third column. Note that the first entry of the fourth column will be empty, 0 or -, because, there is no entry before the fisrt entry of column three. Thanks in advance!
##### 3 CommentsShowHide 2 older comments
See this thread:
Your problems weren't caused by that, though. It's just good practice not to shadow native MATLAB functions.

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