please help me with this calculus question

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)

[Matt J]

We don't know what you expect. The result that I get doesn't surprise me.

Answer 1

[David Hill]

No reason to use symbolics.

round(sum((-1).^(2:58)./(1:57).^2),4);

[Matt J]

Should be,

round(sum((-1).^(0:56)./(1:57).^2),4)

[zidan masood]

why am i getting this error when i run your code

Invalid call to round. Correct usage is:

-- round (X)

[David Hill]

Did you copy and past it into your command line? The above code works.

[Star Strider]

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;

.