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AP EAMCET · Maths · Complex Number

If \(\omega\) is a complex cube root of unity, the \(\left[\frac{51+73 \omega+87 \omega^2}{73+87 \omega+51 \omega^2}+\frac{51+73 \omega+87 \omega^2}{87+51 \omega+73 \omega^2}\right]=\)

  1. A 1
  2. B -1
  3. C 0
  4. D 2
Verified Solution

Answer & Solution

Correct Answer

(B) -1

Step-by-step Solution

Detailed explanation

\begin{aligned} & \left[\frac{51+73 \omega+87 \omega^2}{73+87 \omega+51 \omega^2}+\frac{51+73 \omega+87 \omega^2}{87+51 \omega+73 \omega^2}\right]^{15} \\ & =\left[\begin{array}{c}\frac{51 \omega^2+73 \omega^3+87 \omega^4}{73+87 \omega+51 \omega^2} \times \frac{1}{\omega^2} \\…