how to write this code to generate what i want

Hi! I'm trying to write a code in mesh to ilustrate some a surface that in determined by the ecuation:

x,y,z are all coordonates on the axis. the surface should look like this:

but i can't get it to look the same. My code is:

clear all; close all; clc;
xmin=-pi;xmax=pi;nx=50;
x=linspace(xmin,xmax,nx);
ymin=-pi;ymax=pi;ny=50;
y=linspace(ymin,ymax,ny);
[X,Y]=meshgrid(x,y);
alfa=59*pi/180;
Z=sqrt(X.^2./tan(alfa)^2)+sqrt(Y.^2./tan(alfa)^2);
figure
mesh(X,Y,Z);
axis equal

can anyone please help me?

Answer 1

[Voss]

clear all; close all; clc;
xmin=-pi;xmax=pi;nx=50;
x=linspace(xmin,xmax,nx);
ymin=-pi;ymax=pi;ny=50;
y=linspace(ymin,ymax,ny);
[X,Y]=meshgrid(x,y);
alfa=59*pi/180;
% Z=sqrt(X.^2./tan(alfa)^2)+sqrt(Y.^2./tan(alfa)^2);
Z=sqrt((X.^2+Y.^2)./tan(alfa)^2);
figure
mesh(X,Y,Z);
hold on
mesh(X,Y,-Z);
axis equal

[Voss]

You can also leave alfa in degrees and use tand instead of tan.

https://www.mathworks.com/help/matlab/ref/double.tand.html

[Alexandra-Anamaria]

Thanl you! You helped me a lot!

[Voss]

You're welcome! Any questions, let me know. Thanks!