Question

Find the local maximum and minimum values and saddle point(s) of the function. If you have three-dimensional graphing software, graph the function with a domain and viewpoint that reveal all the important aspects of the function. (Enter your answers as a comma-separated list. If an answer does not exist, enter DNE.)

f (x, y) = xy − 5x − 5y − x² − y²

local maximum value(s)
local minimum value(s)			DNE
saddle point(s)	(x, y, f)	=DNE

Answer 1

Saddle point : The critical point at which function does not attain either maxima or minima,is called saddle point.

Since here only one critical point at which function attains maxima,so there is no saddle point.

If you have any doubt then please comment.