Plotting X Y Z

hey guy's i'm having some error every time i plot this one. 16*x^2+36*y^2-9*z^2=144 i used this one.

ezplot('16*x^2+36*y^2-9*z^2=144')

but whenever i used ezplot this error always appear.

??? Error using ==> char Cell elements must be character arrays.

i also tried ezplot3('16*x^2+36*y^2-9*z^2=144')

and error like this appears

??? Index exceeds matrix dimensions.

Error in ==> ezplot3 at 56 [y,y0,yargs] = ezfcnchk(args{2},0,'t');

Error in ==> ezplot at 160 fmsg = char(f);

help me please. i want to plot in 3D

Answer 1

[Patrick Kalita]

This is simply not what ezplot is designed to do. The documentation for ezplot says that it can plot an explicit function of one variable. You are providing an implicit function of three variables. For this task you should be looking at the isosurface command.

Example:

[x,y,z] = meshgrid( linspace( -10, 10, 20 ) );
f = 16*x.^2 + 36*y.^2 - 9*z.^2;
isosurface(x, y, z, f, 144)

Answer 2

[Wayne King]

Hi, I think you might want:

   ezmesh('16/9*x.^2+4*y.^2-16')

[Walter Roberson]

The negative of that needs to be done as well.

Answer 3

[Walter Roberson]

ezplot() cannot deal with functions with 3 variables.

I do not know if ezplot3() can.