I believe ezsurf
comes close to what you want. You would first have to solve each equation for z
, then make a function for that equation and plot it with ezsurf
. Here's how to do it with your first equation from above:
func1 = @(x, y) sqrt(1-x.^2-y.^2);
ezsurf(func1);
This should display the upper half of a sphere.
To display all three equations together, you can do the following:
func1 = @(x, y) sqrt(1-x.^2-y.^2);
func2 = @(x, y) 0.5.*x.^2+0.25.*y.^2;
func3 = @(x, y) sqrt(4.*y-3.*x.^2);
ezsurf(func1, [-1 1 -1 1]);
hold on;
ezsurf(func2, [-1 1 -1 1]);
ezsurf(func3, [-1 1 -1 1]);
axis([-1 1 -1 1 0 1]);
and the resulting plot will look like this:
By rotating the plot, you will notice that there appear to be two points where all three surfaces intersect, giving you two solutions for the system of equations.