how to compute the limit as N goes to infinity of a summation from -N to N

Hi all - While making this sort of computation is a breeze in Mathematica I am trying to figure out how to accomplish it in Matlab (with my fairly limited skills) and am not making much progress. This is my first post here and while I realize that most people usually code in the equations I have not yet figured out how to do so. So instead I have attached a photo of the equation I am trying to solve. Any insight would be greatly appreciated.

Answer 1

[Torsten]

"symsum" together with "limit" do not succeed ?

https://de.mathworks.com/help/symbolic/symsum.html

https://de.mathworks.com/help/symbolic/limit.html

syms N n 
limit(symsum(1/(2*N+1)*9*(cos(n/7-Pi/8))^2,n,-N,N),N,Inf)

Best wishes

Torsten.