Past exam of the mathematics course of the University of Cambridge 2023 ii Paper 2 13E b ii Solution Created 2026-09-24 Updated 2026-09-25
At , the branch value is the complete elliptic integral of the first kindA contour that goes once around and then to applies the reflection about , giving
Similarly, the branch value at is , so a loop around acts as . A contour that loops first around and then around therefore gives
Finally approach the interval through the upper half-plane. Thereso the branch value at isIt follows that a loop around acts asA contour that loops first around and then around consequently givesHere is the complementary complete elliptic integral of the first kind. These contours exhibit all three requested values.