function ps10_q3_sol

     nx = 50;
     nt = 50;
     tend = 0.1;
     m = 1000;

     x = [0:1.0/nx:1];
     t = [0:tend/nt:tend];

     S = zeros(length(t),1) * x;
     for j=1:m

        S = S - (2.0*(-1)^j/(j*pi) + 4.0*(1-(-1)^j)/(j*pi)^3) * ...
            exp(-j^2*pi^2*t)' * sin(j*pi*x);

     end

     surf(x,t,S);

