MathDB
Mathlete's log: this is an awfully complex problem! (BMT 2019 Discrete #9)

Source:

May 26, 2019

Problem Statement

Let z=12(2+i2) z = \frac{1}{2}(\sqrt{2} + i\sqrt{2}) . The sum k=01311zekiπ7 \sum_{k = 0}^{13} \dfrac{1}{1 - ze^{k \cdot \frac{i\pi}{7}}} can be written in the form abi a - bi . Find a+b a + b .