a) Let f(x)=x 2
−x 2
y 2
+4y 2
. Assuming that f has exactly the five critical points: (0,0),(2,1),(−2,1),(2,−1),(−2,−1) use the Second Partials Test to locate all relative maxima, relative minima, and saddle points, if any. b) Use Lagrange multipliers to find the absolute extrema of f(x,y)=xy 2
−2x 3
on the circle x 2
+y 2
=9