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zidan masood on 9 Oct 2021
Commented: Star Strider on 9 Oct 2021
this is the question:
Consider the sum A inferred by the following:
A = 1 -1/4 + 1/9 - 1/16 + 1/25...
If the 1st term is t1 = 1 and the 2nd term is t2 = -1/4, use MATLAB to determine the sum
of terms at the 57th term (i.e. including the 57th term). Give answer to 4 decimal places. Also, provide MATLAB code.
this is my Matlab code but its not giving me the answer i expect. please help me with this. thank you
syms n x
F(x)=symsum((-1)^(n-1)/n^2,n,1,57)
##### 1 CommentShowHide None
Matt J on 9 Oct 2021
We don't know what you expect. The result that I get doesn't surprise me.

David Hill on 9 Oct 2021
Edited: David Hill on 9 Oct 2021
No reason to use symbolics.
round(sum((-1).^(2:58)./(1:57).^2),4);
Star Strider on 9 Oct 2021
See the documentation section on Compatibility Considerations. (It always helps to use the Release window to post the release being used.)
It is easy to emulate the version introduced in R2014b
roundn = @(x,n) round(x .* 10.^n)./10.^n;
.