Plot a elliptic cone

Hello there, I have this given equations of elliptic cone x^2 + 4*y^2 = z^2 and now I want to plot it.

I have try this but it seems to be incorrect.

f = @(x,y,z) x.^2 + 4*y.^2 - z.^2
fimplicit3(f,[-100,100])

How can I plot that function? Thanks in advance.

Answer 1

[madhan ravi]

axis equal

Answer 2

[KSSV]

I can plot a ellipse like this:

x = linspace(-2,2) ; 
y = linspace(-2,2) ; 

m = 100 ; n = 100 ; 
theta = linspace(0,2*pi,m);
R = linspace(0,8,n) ;
[T R] = meshgrid(theta,R) ;
% Convert grid to cartesian coordintes
X = R.*cos(T) ; 
Y = R.*sin(T) ;
Z = R ;

surf(X,Y,Z)