Solution

ID: past-exam-of-the-mathematics-course-of-the-year-1-of-the-natural-sciences-course-of-the-university-of-cambridge/2018/paper-2/13/a/i/solution

Starting at , traverse the right, top, left and bottom sides in that order. For , the differential expression is . The four line integral contributions are respectively , so the total is two.
For , the expression is . The right side contributes , and the top side contributes ; the other sides contribute zero. Therefore

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