let f(x,y)=kx2 y2−8xy
.

(a) Determine the values of
(if any) for which the critical point at (0,0)
is a saddle point.

Select answer from the options below

<9

≥9

There are no such values of
.

(b) Determine the values of
(if any) for which the critical point at (0,0)
is a local maximum.

Select answer from the options below

<9

≥9

There are no such values of