jee-main 2022 Q63

jee-main · India · session1_27jun_shift1 Complex numbers 2 Roots of Unity and Cyclotomic Properties

The value of $\cos \left( \frac { 2 \pi } { 7 } \right) + \cos \left( \frac { 4 \pi } { 7 } \right) + \cos \left( \frac { 6 \pi } { 7 } \right)$ is equal to
(1) $- 1$
(2) $- \frac { 1 } { 2 }$
(3) $- \frac { 1 } { 3 }$
(4) $- \frac { 1 } { 4 }$

The value of $\cos \left( \frac { 2 \pi } { 7 } \right) + \cos \left( \frac { 4 \pi } { 7 } \right) + \cos \left( \frac { 6 \pi } { 7 } \right)$ is equal to\\
(1) $- 1$\\
(2) $- \frac { 1 } { 2 }$\\
(3) $- \frac { 1 } { 3 }$\\
(4) $- \frac { 1 } { 4 }$

Paper Questions

Q61 Q62 Q63 Q64