How could I sums up 1/n for n=1 to 10000?

Question

Wenchen Liu 2022-9-23

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1810470-how-could-i-sums-up-1-n-for-n-1-to-10000

评论： Walter Roberson 2022-9-23

I have a code like this, but I can't run it.

n = 10000; % whatever you want
sum_harm = 0;
for i = 1:n
    sum_harm = sum_harm + 1/i;
end
sum_harm
sum_harm = 9.7876

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Answer 1

Chunru 2022-9-23

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https://ww2.mathworks.cn/matlabcentral/answers/1810470-how-could-i-sums-up-1-n-for-n-1-to-10000#answer_1059085

It can be run as shown below. What problem have you encountered?

n = 10000; % whatever you want
sum_harm = 0;
for i = 1:n
   sum_harm = sum_harm + 1/i;
end
sum_harm
sum_harm = 9.7876

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Chunru 2022-9-23

There is no variables called "result". You should check "sum_harm" after running your code.

To see the intermediate partial sum, simply remove semicolon at the end of sum statement as shown below:

n = 10; % whatever you want
sum_harm = 0;
for i = 1:n
   sum_harm = sum_harm + 1/i    % ; suppress display;  remove it for display
end
sum_harm = 1
sum_harm = 1.5000
sum_harm = 1.8333
sum_harm = 2.0833
sum_harm = 2.2833
sum_harm = 2.4500
sum_harm = 2.5929
sum_harm = 2.7179
sum_harm = 2.8290
sum_harm = 2.9290
sum_harm
sum_harm = 2.9290

Walter Roberson 2022-9-23

n = 1:10000;

result = cumsum(1./n);

result(end)

ans = 9.7876

plot(n, result)

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Answer 2

Image Analyst 2022-9-23

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1810470-how-could-i-sums-up-1-n-for-n-1-to-10000#answer_1059100

Why not try it vectorized:

n = 1 : 10000; % whatever you want
sum_harm = sum(1 ./ n)
sum_harm = 9.7876

What problem did you have in running your code? It ran in MATLAB online. Did you type the m-file name into the command window or click the green run triangle on the tool ribbon? Either should work, but what did you do, if anything? Why do you say you can't run it? Why do you not know how to run the code? Try this link if you don't know how to run your MATLAB program:

MATLAB Academy - Free 2 hour training