Plotting discrete time signals involving sumations in matlab.

Question

Many of the examples I've encountered while looking for an answer are simple functions that do not involve summations.

Suppose I have the following function;

f(n) = sum(n*cos(n-k)) from k=-infinity to infinity

How would I go about making the discrete plot in MATLAB?

Answer 1

f = 0;
n = linspace(-6*pi, 6*pi, 5000);     
k = -100;

for i = -k:k
    f = f + n*cos(n - i);
end

plot(n, f)
stem(n, f)