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AP EAMCET · Maths · Trigonometric Equations

In \(\triangle P Q R\), let \(\angle P>\angle Q\). If the radian measures of \(\angle P\) and \(\angle Q\) satisfy the equation \(4 \sin ^3 x-3 \sin x+a=0,0 < a < 1\), then the radian measure of \(\angle R\) is

  1. A \(\frac{\pi}{3}\)
  2. B \(\frac{\pi}{2}\)
  3. C \(\frac{2 \pi}{3}\)
  4. D \(\frac{5 \pi}{6}\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(\frac{2 \pi}{3}\)

Step-by-step Solution

Detailed explanation

Given, \(4 \sin ^3 x-3 \sin x+a=0\) \(\begin{aligned} \Rightarrow & & a & =3 \sin x-4 \sin ^3 x \\ \Rightarrow & & a & =\sin 3 x \\ & \ddots & \sin 3 P & =a=\sin 3 Q \end{aligned}\) [since \(P\) and \(Q\) satisfy the equation]…