Plot of infinite fourier form

I have a summatory of Fourier with this form:

I need to plot values of x aproaching to 0, i declared symbolic variables using n and x and used fplot but i realized fplot makes the value between -1 and 1 not the sum up. For every value of x i need to know every little contribution which aproaches to c0 this means summatory and N1 tends to 0 when x apraches to 0, how can i plot that?

Thanks