What's the minimum or maximum of U?
Differentiating I get:
So, is it correct to say that both the partial differentials are constant, therefore there is no minimum or maximum?
We're expected to equate the partial derivaitves to zero, and solve.
What's the minimum or maximum of ?
Since I could see that can increase without bound,
. . I suspected that we had found a minimum value.
Then I tried the Second Partials Test . . .
. . . .
. . . . negative
Therefore: . .is a saddle point.
. . The function has neither a maximum nor a minimum.