Calculate all four second-order partial derivatives and check that [math]. Assume the variables are restricted to a domain on which the function is defined. [math]
[math]
[math]
[math]
[math]
Consider the partial derivatives [math] [math] Is there a function [math] which has these partial derivatives?
If so, what is it?
[math]
(Enter none if there is no such function.)
Determine the sign of [math] and [math] at each indicated point using the contour diagram of [math] shown below. (The point [math] is that in the first quadrant, at a positive [math] and [math] value; [math] through [math] are located clockwise from [math], so that [math] is at a positive [math] value and negative [math], etc.)
(a) At point [math],
[math] is and
[math] is .
(b) At point [math],
[math] is and
[math] is .
(c) At point [math],
[math] is and
[math] is .
The plane [math] intersects the surface [math] in a certain curve. Find the slope to the tangent line to this curve at the point [math].
[math]
Find the partial derivatives of the function [math]
[math]
[math]