Objectives:
1.
Understand how to compute a partial derivative.
2.
Know what the partial derivative represents geometrically.

Recap Video

The following video recaps the main ideas of the section.

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Problems

If , then:
If , then:
If , then:
If , then
If , then:

If , then .
Use Clairaut’s theorem to reorder the partials.
The contour map of function is shown below.
PIC
The partial is positivenegativezero and is positivenegativezero .
What are the -values doing as you move in the and directions?