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AP EAMCET · Maths · Trigonometric Equations

Number of solutions of the equation \(\cos \theta+\cos 2 \theta-\sqrt{3}(\sin \theta+\sin 2 \theta)+1=0\) lying in the interval \((0,2 \pi)\) is

  1. A 3
  2. B 6
  3. C 5
  4. D 4
Verified Solution

Answer & Solution

Correct Answer

(D) 4

Step-by-step Solution

Detailed explanation

\(\cos \theta+\cos 2 \theta-\sqrt{3}(\sin \theta+\sin 2 \theta)+1=0\) \(\cos \theta + (2\cos^2\theta - 1) - \sqrt{3}(\sin \theta + 2\sin\theta\cos\theta) + 1 = 0\) \(\cos \theta + 2\cos^2\theta - \sqrt{3}\sin \theta - 2\sqrt{3}\sin\theta\cos\theta = 0\)…