Answer
(a) Using graph we can approximate $f(3,2)\approx \frac{50+60}{2}=55$
(b) $f_x(3,2)$ is negative because functional value decreases if $x$ increases.
(c) $f_y(2,1)$ is larger because level curves are closer at$(2,1)$ as compared to $(2,2)$.
Work Step by Step
(a) Using graph we can approximate $f(3,2)\approx \frac{50+60}{2}=55$
(b) $f_x(3,2)$ is negative because functional value decreases if $x$ increases.
(c) $f_y(2,1)$ is larger because level curves are closer at$(2,1)$ as compared to $(2,2)$.