Let f(x,y) = x²- y² On each of the restricted domains listed below, say whether f(x,y) has a global max and/or global min, and if so, at what points?
(a) All of R²
(b) On the circle x²+y²=4
(c) On the line x+2y=1
(d) On the disk x²+y²≤4
(e) On the region where x²+y² ≤4 and y≥1
