Multi-Variable Curves & Surfaces

Instead of areas like normal functions, Multi-variable Functions define surfaces

To be able to draw these 3d shapes in 2d, we fix one of the independent variables to get a trace (2D graph)

• Traces are the intersection of the surface with the plane $x\text{ (or }y)=$ constant

Level curves are the intersection of the surface with the $z=\text{constant}$ (dependent variable)