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TS EAMCET · Maths · Complex Number

If \(\alpha\) is a root of the equation \(x^2-x+1=0\), then \(\left(\alpha+\frac{1}{\alpha}\right)^3+\left(\alpha^2+\frac{1}{\alpha^2}\right)^3+\left(\alpha^3+\frac{1}{\alpha^3}\right)^3+\left(\alpha^4+\frac{1}{\alpha^4}\right)^3=\)

  1. A \(0\)
  2. B \(1\)
  3. C \(-3\)
  4. D \(-9\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(-9\)

Step-by-step Solution

Detailed explanation

\(\begin{aligned} & \text { } x^2-x+1=0 \\ & \alpha^2-\alpha+1=0 \Rightarrow \alpha+\frac{1}{\alpha}=1 \\ & \Rightarrow \alpha^2+\frac{1}{\alpha^2}+2=1 \Rightarrow \alpha^2+\frac{1}{\alpha^2}=-1\end{aligned}\)…