Q. If $\omega$ is acomplex cube root of unity, then the value of $\sin\left\{ \left( \omega^{10} + \omega^{23} \right)\pi - \frac{\pi}{6} \right\}$ is

A) $\frac{1}{\sqrt{2}}$
B) $\frac{\sqrt{3}}{2}$
C) $- \frac{1}{\sqrt{2}}$
D) $\frac{1}{2}$
Explanation

(d)
Since, $\omega$ is a complex cube root of unity
Now, $\omega^{10} + \omega^{23} = \left( \omega^{3} \right)^{3}\omega + \left( \omega^{3} \right)^{7}\omega^{2}$
$= \omega + \omega^{2} = - 1$
$\therefore\ \ \sin\left\{ \left( \omega^{10} + \omega^{23} \right)\pi - \frac{\pi}{6} \right\} = \sin\left( - \pi - \frac{\pi}{6} \right) = \sin{\frac{\pi}{6} = \frac{1}{2}}$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.