Quantitative Aptitude Ques 1473
Question: If $ \sin 5\theta =\cos 20{}^\circ (0{}^\circ <\theta <90{}^\circ ), $ then the value of $ \theta $ is [SSG (CGL) Mains 2014]
Options:
A) $ 4{}^\circ $
B) $ 22{}^\circ $
C) $ 10{}^\circ $
D) $ 14{}^\circ $
Show Answer
Answer:
Correct Answer: D
Solution:
- Given, $ \sin 5\theta =\cos 20{}^\circ $
$ \Rightarrow $ $ \sin 5\theta =\sin (90{}^\circ -20{}^\circ ) $
$ \Rightarrow $ $ 5\theta =90{}^\circ -20{}^\circ $
$ \Rightarrow $ $ 5\theta =70{}^\circ $
$ \therefore $ $ \theta =14{}^\circ $
BETA
