please help me, how do I make the code for the equation in the following picture?

[Tommy]

If you have the symbolic math toolbox:

syms n;
double(symsum(sin(2*n)/n^2,1,inf))

[Muhammad Rohim]

Thanks

[darova]

You can use 200 percent scale for the picture if you want

Answer 1

[Peter O]

You can't code an infinite sum exactly, but fortunately, this one is bounded (x^2 on the denominator and the numerator is bounded between -1 and 1).

Pick a big n:

n_max=100;
ns = 1:n_max;
sum_n = cumsum( sin(2*ns)./ns.^2);
plot(ns, sum_n)

You will see it very quickly converges, after 20 terms or so.

[Muhammad Rohim]

Thank you

[Muhammad Rohim]

Can i ask, why the code above doesn't work? displayed that an error occurred: the brackets or brackets are out of balance or unexpected

[Peter O]

Muhammed,

I'm not sure. I copied the code block directly from the response to check and it seemed to run in the command line without a problem. Generally you get that error if there is an unclosed parenthesis in an expression: each '(' gets a ')'. If you typed it manually, perhaps double-check your entry? The space between the opening parenthesis of the cumsum function and the sin function can also be removed, although that shouldn't make a difference.

[Muhammad Rohim]

Thank you very much. It ia work.

[Ameer Hamza]

"You can't code an infinite sum exactly"

Peter, I think you meant the opposite.