The value of

MATHEMATICS · Single correct · CBSE · Mathematics · Complex Numbers and Quadratic Equations · Complex Numbers and Quadratic Equations

Problem

The value of

\sum_{k=1}^{6} \left( \sin \left( \frac{2\pi k}{7} \right) - i \cos \left( \frac{2\pi k}{7} \right) \right)

, where

i = \sqrt{-1}

, is (1)

-1

(2) 0 (3)

-i

(4)

i