Fxy in a contour graph, positive or negative?

[kougou]

Homework Statement

d=1352846320

The question asks for fxy.
The rate of change of (the rate of change of f in the x direction) in the y-direction.


We know fx is negative because as f moves in the x-direction, f decreases. But how do I know the rate of change of fx in the y-direction? Any idea?

Thank

 

[Mark44]

Homework Statement

d=1352846320View attachment 52924The question asks for fxy.
The rate of change of (the rate of change of f in the x direction) in the y-direction. We know fx is negative because as f moves in the x-direction, f decreases. But how do I know the rate of change of fx in the y-direction? Any idea?

Thank

What is being shown in the graph? Are these level curves for z = f(x, y)?

We know fx is negative because as f moves in the x-direction, f decreases.

f is not moving. A point (x, y) in the plane is moving, which results in different values of something. I can't tell what "something" is, because your graph has no labels that would help me understand what it is conveying.