Add another column to the right end of this array

Question

Jose Ceballos 2023-3-29

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1937509-add-another-column-to-the-right-end-of-this-array

评论： Jose Ceballos 2023-3-29

This a code within the book of Cengels' Differential Equations. I would like to add a column with the value exact (1.5) at the right side at the end of the array.

lower=0;upper=1;

m=1;

exact=1.5;

f=@(x)7*x-6*x^2;

for nstrip=[1,2,3,4,5,10:10:50,100,200]

h=(upper-lower)/nstrip;

x=lower;value=0;

for n=1:nstrip

value=value+h*(f(x)+f(x+h))/2;

x=x+h;

error(m,:)=[nstrip,value,100*abs(value-exact)/exact];

end

m=m+1;

end

error

This is what I obtain:

I would like to obtain this

thanks for your help

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Answer 1

James Tursa 2023-3-29

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1937509-add-another-column-to-the-right-end-of-this-array#answer_1204089

在 MATLAB Online 中打开

your_matrix(:,end+1) = 1.5;

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Torsten 2023-3-29

编辑：Torsten 2023-3-29

在 MATLAB Online 中打开

lower=0;upper=1;
m=1;
exact=1.5;
f=@(x)7*x-6*x^2;
Nstrip=[1,2,3,4,5,10:10:50,100,200];
my_results = zeros(numel(Nstrip),4);
for nstrip=Nstrip
    h=(upper-lower)/nstrip;
    x=lower;value=0; 
    for n=1:nstrip
        value=value+h*(f(x)+f(x+h))/2;
        x=x+h; 
    end
    my_results(m,:) = [nstrip,value,100*abs((value-exact)/exact),exact];
    m=m+1;
end
my_results
my_results = 12×4
    1.0000    0.5000   66.6667    1.5000
    2.0000    1.2500   16.6667    1.5000
    3.0000    1.3889    7.4074    1.5000
    4.0000    1.4375    4.1667    1.5000
    5.0000    1.4600    2.6667    1.5000
   10.0000    1.4900    0.6667    1.5000
   20.0000    1.4975    0.1667    1.5000
   30.0000    1.4989    0.0741    1.5000
   40.0000    1.4994    0.0417    1.5000
   50.0000    1.4996    0.0267    1.5000