Let f(x,y)= x⁽³⁾y- xy⁽⁴⁾. Estimate the absolute maximum of f(x,y) on the regionx⁽²⁾+ y⁽²⁾≤1.
a) Maximum is at (0,0)
b) Maximum is at (-1,-1)
c) Maximum is at (1,1)
d) Maximum is at (-1,1)