Complex Numbers And Quadratic Equations question 250

Question: The value of $ \frac{a+b\omega +c{{\omega }^{2}}}{b+c\omega +a{{\omega }^{2}}}+\frac{a+b\omega +c{{\omega }^{2}}}{c+a\omega +b{{\omega }^{2}}} $ will be [BIT Ranchi 1989; Orissa JEE 2003]

Options:

A) 1

B) - 1

C) 2

D) - 2

Show Answer

Answer:

Correct Answer: B

Solution:

Multiplying the numerator and denominator by $ \omega $ and $ {{\omega }^{2}} $ respectively I and II expressions $ =\frac{a+b\omega +c{{\omega }^{2}}}{b+c\omega +a{{\omega }^{2}}}+\frac{a+b\omega +c{{\omega }^{2}}}{c+a\omega +b{{\omega }^{2}}} $ $ =\frac{\omega (a+b\omega +c{{\omega }^{2}})}{(b\omega +c{{\omega }^{2}}+a)}+\frac{{{\omega }^{2}}(a+b\omega +c{{\omega }^{2}})}{(c{{\omega }^{2}}+a+a\omega )}=\omega +{{\omega }^{2}}=-1 $