Drawing a hyperboloid with polar coordinates

Hi all!

I have received the following problem to solve:

Draw the surface of the hyperboloid with the equation:

when

Also, the polar coordinates for x and y must be used, i.e.:

I have converted the equation of the hyperboloid so that it became:

I could then express z as:

I have the following code so far:

r = linspace(0,1,21);
a = linspace(0,2*pi,63);
[R,A] = meshgrid(r,a);
X = R.*cos(a);
Y = R.*sin(a);
Z = square((R.^2)-1);
surf(X,Y,Z);
axis equal

However, when ever I run the program I get a cylinder instead. I think the problem might be that the values of z should be between -3 and 3, however I do not know how to express this in the code. I would appricate any help that I get. Thank you for everyone in advance!

Answer 1

[Mathieu NOE]

hello

you have to start from z and then compute r and not vice versa

also square root function is sqrt and not square

z = linspace(-3,3,21);
a = linspace(0,2*pi,63);
[Z,A] = meshgrid(z,a);
R = sqrt((Z.^2)+1);

X = R.*cos(A);
Y = R.*sin(A);
surf(X,Y,Z);
axis equal

[Szabolcs Simon-Guth]

Alright! Thank you very much for the help! I really appreciate it. I'm new to MATLAB and did not think of doing it the other way around. Much obliged! :)

[Mathieu NOE]

My pleasure !