[X,Y] = meshgrid(-3:0.1:3);
mu = [0,0];
sigma = [1,1];
rho = 0.0;
Xstand = (X-mu(1))/sigma(1);
Ystand = (Y-mu(2))/sigma(2);
Z = exp(-(Xstand.^2+Ystand.^2-2*rho.*Xstand.*Ystand)/(2*(1-rho^2)))/(2*pi*sigma(1)*sigma(2)*sqrt(1-rho^2));
surf(X,Y,Z)
