Exercise 5–8 Determine Signs of Partial Derivatives

Determine the signs of the partial derivatives for the function \(f\) whose graph is shown.

5.
(a) \(f_x(1, 2)\)
(b) \(f_y(1, 2)\)

6.
(a) \(f_x(-1, 2)\)
(b) \(f_y(-1, 2)\)

7.
(a) \(f_{xx}(-1, 2)\)
(b) \(f_{yy}(-1, 2)\)

8.
(a) \(f_{xy}(1, 2)\)
(b) \(f_{yx}(1, 2)\)