Determine the sign of [math] and [math] at each indicated point using the contour diagram of [math] shown below. (The point [math] is that in the first quadrant, at a positive [math] and [math] value; [math] through [math] are located clockwise from [math], so that [math] is at a positive [math] value and negative [math], etc.)

(a) At point [math],
[math] is and
[math] is .

(b) At point [math],
[math] is and
[math] is .

(c) At point [math],
[math] is and
[math] is .

Solution: