Complex Numbers And Quadratic Equations question 252

Question: $ {{( -\frac{1}{2}+\frac{\sqrt{3}}{2}i )}^{1000}}= $

Options:

A) $ \frac{1}{2}+\frac{\sqrt{3}}{2}i $

B) $ \frac{1}{2}-\frac{\sqrt{3}}{2}i $

C) $ -\frac{1}{2}+\frac{\sqrt{3}}{2}i $

D) None of these

Show Answer

Answer:

Correct Answer: C

Solution:

Here $ -\frac{1}{2}+\frac{1}{2}i\sqrt{3} $ is one of the two imaginary cube root of unity. If we denote it by $ \omega $ . Then $ {{\omega }^{1000}}={{\omega }^{999}}\omega ={{({{\omega }^{3}})}^{333}}\omega =\omega =-\frac{1}{2}+\frac{\sqrt{3}}{2}i $ .