Consider the 3d graph of a quadratic form: 1/2*trans(x)*A*x-trans(b)*x(adsbygoogle = window.adsbygoogle || []).push({});

Plot via matlab: surfc(X,Y,Z);

add following lines:

hold on

x=-10:10;

y=0.5*(2-3*x);

plot(x,y);

This plot a straight line which intersects the 3d surface. However, I wish for it be graphed on the contours: i.e. the 3d graph has contours where Z=-200. The plot(x,y) plots the straight line on the z=0 plane. I wish for it graph the straight line on the z=-200 plane.

I've considered doing a loops such that I graph single points for the z=-200 plane.

Thank you.

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# MATLAB: Adding 2d plot to 3d surface

Can you offer guidance or do you also need help?

Draft saved
Draft deleted

**Physics Forums | Science Articles, Homework Help, Discussion**