jee-main 2017 Q89

jee-main · India · 09apr Complex numbers 2 Roots of Unity and Cyclotomic Properties
The value of $\sum _ { k = 1 } ^ { 10 } \left( \sin \frac { 2 k \pi } { 11 } + i \cos \frac { 2 k \pi } { 11 } \right)$ is:
(1) 1
(2) $- 1$
(3) $- i$
(4) $i$
The value of $\sum _ { k = 1 } ^ { 10 } \left( \sin \frac { 2 k \pi } { 11 } + i \cos \frac { 2 k \pi } { 11 } \right)$ is:\\
(1) 1\\
(2) $- 1$\\
(3) $- i$\\
(4) $i$