Trigonometric Equations Question 340

Question: If $ 2\sin \theta +\tan \theta =0 $ , then the general values of $ \theta $ are

Options:

A) $ 2n\pi \pm \frac{\pi }{3} $

B) $ n\pi ,2n\pi \pm \frac{2\pi }{3} $

C) $ n\pi ,2n\pi \pm \frac{\pi }{3} $

D) $ n\pi ,n\pi +\frac{2\pi }{3} $

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Answer:

Correct Answer: B

Solution:

  • $ 2\sin \theta +\tan \theta =0 $ ; $ \sin \theta ( 2+\frac{1}{\cos \theta } )=0 $ i.e., $ \sin \theta =0\Rightarrow \theta =n\pi $ or $ \frac{1}{\cos \theta }=-2\Rightarrow \cos \theta =-\frac{1}{2}\Rightarrow \theta =2n\pi \pm ( \frac{2\pi }{3} ) $ .