A contour diagram of is given in the figure. Determine whether and are positive, negative, or zero at the points P, Q, R, and S.

 1. at the point Q.

 2. at the point R.

 3. at the point S.

 4. at the point S.

 5. at the point P.

 6. at the point P.

 7. at the point R.

 8. at the point Q.

 

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You can earn 50% partial credit for 4 - 5 correct answers, and 75% partial credit for 6 - 7 correct answers.