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AP EAMCET · Maths · Complex Number

If \(\frac{3-2 i \sin \theta}{1+2 i \sin \theta}\) is purely imaginary number, then \(\theta=\)

  1. A \(2 n \pi \pm \frac{\pi}{4}\)
  2. B \(2 n \pi \pm \frac{\pi}{2}\)
  3. C \(n \pi \pm \frac{\pi}{3}\)
  4. D \(n \pi \pm \frac{\pi}{6}\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(n \pi \pm \frac{\pi}{3}\)

Step-by-step Solution

Detailed explanation

\(\frac{3-2 i \sin \theta}{1+2 i \sin \theta}=\frac{(3-2 i \sin \theta)(1-2 i \sin \theta)}{1+4 \sin ^2 \theta}=\frac{3-4 \sin ^2 \theta}{1+4 \sin ^2 \theta}\) From the given information real part \(=0\)…