MATLAB Answers

Calculating results for Partial Sums

50 views (last 30 days)
Kyle Donk
Kyle Donk on 10 Jan 2020
Commented: ME on 18 Jan 2020
My question is:
Calculate the result and absolute error for each partial sum: N = 10, 160, and 640. You should use for-loops and not commands like symsum.
I keep on getting weird answes in Matlab and was wondering if my code was missing something:
%(a) Calculate the result and absolute error for each partial sum: N = 10, 160, and 640.
sum=0;
for N=[10 160 640]
for n=1:1:N
y=1/n^2
end
sum=sum+1
error=((pi^2)/6)-sum
end
disp(sum)
PLEASE DO NOT GIVE ME THE COMPLETE ANSWER TO THE QUESTION. I WOULD JUST LIKE AN EXPLANATION OF WHAT I AM DOING WRONG.

  0 Comments

Sign in to comment.

Accepted Answer

ME
ME on 10 Jan 2020
The main problem here is that you arent actually summing the y values as you go along. You are not adding y to the sum like you should, instead you are calculating all of the y values, ignoring them and adding 1 to the sum instead.
You would also probably be better off indexing your sum and error values so that you get one value for each of the Ns you input.
You have asked not to see the code so I haven't included it, but please comment below if you'd like me to add it!

  5 Comments

Show 2 older comments
ME
ME on 17 Jan 2020
Did you manage to get this working in the end?
I still have the code if you haven't been able to figure it out.
Also, if you found my answers helpful, then could you possibly accept my answer?
Image Analyst
Image Analyst on 18 Jan 2020
The secondary problems are using sum and error for variable names. Don't use built-in function names for variable names.
ME
ME on 18 Jan 2020
Absolutely, this is a good point. It won’t cause any issues in this simple case but could be more problematic if this was to be built into something larger.

Sign in to comment.

More Answers (0)

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!