Here is the task:
Find supremum and infimum of , if .
I have tried two ways:
1) searching for partial derivatives in order to find local extrema, but here is what happens:
So, it means that there is no local extreme points at all? Or all are extreme points?
2) from D follows that . Then I can get function and look for extreme points of g(x).
How do you think? Which way could fit? Or am I wrong in both of them?