Answer:
-42
Step-by-step explanation:
The objective is to find the line integral of
around the perimeter of the rectangle with corners (4,0), (4,3), (−3,3), (−3,0), traversed in that order.
We will use <em>the Green's Theorem </em>to evaluate this integral. The rectangle is presented below.
We have that

Therefore,

Let's calculate the needed partial derivatives.

Thus,

Now, by the Green's theorem, we have

The awnser to 60 x 20 is: 120