how do i plot a 3d function and a 2d curve together?

Hi, i'm new to matlab and i need to plot both: (i don't really know if this is possible but it is worth trying)

1) this 3d function:

f(x,y)= (x^2)/(x^2 - y^2) when |x| ≠ |y|

0 when |x| = |y|

and

2) the curve y=mx where m could be all numbers in ℝ or just some of those numbers.

Both graphs should be seen together.

thx!

Answer 1

[KSSV]

m = 100 ; n = 100 ; 
x = linspace(-1,1,m) ;   % define your range of x
y = linspace(-1,1,n) ;   % define your range of y 
[X,Y] = meshgrid(x,y) ; 

Z = X.^2/(X.^2-Y.^2) ; 
Z(X==Y) = 0 ; 

m = rand ; 
y = m*x ; 

surf(X,Y,Z)
hold on
plot3(x,y,zeros(size(x))) ; 

[Vetrimurasu]

If the curve doesn't lie on the surface of the plot, how do one calculate the difference between the curve and the surface plot?