Plotting sum of FFT for Temperature distribution in a contour map

Hi,

I need to plot the following equation:

Taeq=2*c/((n*pi)^3)*((-1)^(n+1)*exp(-((n*pi)^2*t))-((-1)^n)*((n*pi)^2*t-1))*sin(n*pi.*r)./r;

T_a=symsum(Taeq,n,1,300);

in a contour map where r is the radius of a sphere and goes from 0 to 1.

[Kavya Vuriti]

Is 'c' in the expression a variable or constant?