MATLAB: Plot z = x^2 + y^2 over the interval -4 <= x <= +4, -4 <= y <= +4.

homeworkintervalplotting

I'm not sure how to plot above equation. Can anyone help me?

N = 100 ;
x = linspace(-4,4,N) ;
y = linspace(-4,4,N) ;
[X,Y] = meshgrid(x,y) ;
Z = X.^2+Y.^2 ;
surf(X,Y,Z)

 >> x = 0:0.1:3;
 >> y = (x/6).^3;
 >> plot(x,y)

Use the subs (link) function:

X = subs(X, {ztrans(y(n), n, z), y(-1), y(-2)}, {Y(z), 4, 10})

producing:

X =
Y(z) - (3*Y(z))/(2*z) + Y(z)/(2*z^2) - 1/(4*z - 1) + 2/z - 3/2