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TS EAMCET · Maths · Complex Number

If \(z=1-\sqrt{3} i\), then \(z^3-3 z^2+3 z=\)

  1. A 0
  2. B \(1+3 \sqrt{3} i\)
  3. C 1
  4. D \(2+3 \sqrt{3} i\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(1+3 \sqrt{3} i\)

Step-by-step Solution

Detailed explanation

Given, \(z=1-\sqrt{3} i\) \(\begin{aligned} & z^2=1+3 i^2-2 \sqrt{3} i=-2(1+\sqrt{3} i) \\ & z^3=-2(1+\sqrt{3} i)(1-\sqrt{3} i)=-8 \end{aligned}\) Now, \(z^3-3 z^2+3 z=-8+6+6 \sqrt{3} i+3-3 \sqrt{3} i=1+3 \sqrt{3} i\).