Find all points (x, y, z) (x, y, f (x, y)) where the function f(x, y) 4zy 512 -4y2 +15 + 18y + 9 has any relative extrema or saddle points.
Show transcribed image textFind all points (x, y, z) (x, y, f (x, y)) where the function f(x, y) 4zy 512 -4y2 +15 + 18y + 9 has any relative extrema or saddle points.