How to 3D plot equations?

Hi everyone !!! I attempted to plot the following equations, but I am having trouble doing so. Do you think you can help? Thanks.

x^2/9+y^2/16+z^2/9=1 y=5 y^2+z^2=9

Answer 1

[Ameer Hamza]

You can plot them separately using the following code

x = -5:0.1:5;
y = -5:0.1:5;
z = -5:0.1:5;

[X, Y] = meshgrid(x, y);
Z = 3*sqrt(1-X.^2/9-Y.^2/16);
Z(imag(Z)~=0) = inf;
surf(X, Y, Z);

[X, Z] = meshgrid(x, z);
Y = 5*ones(size(X));
figure;
surf(X, Y, Z);

[X, Y] = meshgrid(x, y);
Z = sqrt(9-Y.^2);
Z(imag(Z)~=0) = inf;
figure;
surf(X, Y, Z);

Or you can plot them together using this code

x = -5:0.1:5;
y = -5:0.1:5;
z = -3:0.1:3;

[X, Y] = meshgrid(x, y);
Z = 3*sqrt(1-X.^2/9-Y.^2/16);
Z(imag(Z)~=0) = inf;
surf(X, Y, Z);
hold on

[X, Z] = meshgrid(x, z);
Y = 5*ones(size(X));
% figure;
surf(X, Y, Z);

[X, Y] = meshgrid(x, y);
Z = sqrt(9-Y.^2);
Z(imag(Z)~=0) = inf;
% figure;
surf(X, Y, Z);