The following 2 questions are concerned with the optimization
of functions of 2 variables
1. Find and classify all local extrema
of f(x,y) = x2 + 2y2 -x2y
2. Let
f(x,y = xy - x - y +3 on the triangular region with vertices (0,0),(2,0), and (0,4)
Find the global extrema.