O 1 Oz 2syet -xs at Use the Chain Rule to find Oz yet at when O 2. $ Oz syet -x8 Z = at yet O 3 . = syet -x8 and at yet x = 2set , y =5+ set. 0 4. az = syetxs at yet = 2syet + xs at yet 6. Oz 2syet +xs = at yetLocate and classify the critical point of 1. saddle-point at ( 1, 1) f(x, y) = xy + 2y? -2y - In(xy) 2. local minimum at (1, 1 ) for x, y > 0. 3. local maximum at (2, 4. local maximum at (1, 1) 5. saddle-point at (2, 6. local minimum at (2, NIH