Solution

ID: past-exam-of-the-mathematics-course-of-the-year-2-of-the-natural-sciences-course-of-the-university-of-cambridge/2019/paper-1/3/d/ii/solution

The original PDF shows in the nonzero source branch. Inserting that source into gives, for ,
For , split the integral at :
Because of the homogeneous freedom established in part (i), the full answer to the stated endpoint problem is
At the interface, both branches have value and derivative , so no extra delta or delta derivative occurs there. Direct substitution gives zero source on the left and on the right; the endpoint values are zero for every . If the extra condition is imposed, it selects , but that is additional information absent from the printed question.

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