hello!

i am having trouble with this question:

find the absolute extrema of

defined on a closed region R bounded by the curve

the question mentions that we can view f as a function of some t, for

. Not sure how that helps, however.

to find extrma, we must check the critical points and the endpoints. i know a process for findings the critical points, which may be extrema or saddle points (when partials with respect to x and y both equal to zero). but not sure how to check extrema at endpoints?(the closed circle with radius two)

any help appriciated!

thanks.