Trigonometric Identities Question 115
Question: The expression $ \frac{\cos 6x+6\cos 4x+15\cos 2x+10}{\cos 5x+5\cos 3+10\cos x} $ is equal to
Options:
A) $ cos2x $
B) $ 2,cos,x $
C) $ cos^{2}x $
D) $ 1+\cos x $
Show Answer
Answer:
Correct Answer: B
Solution:
The given expression can be written as $ \frac{(\cos 6x+\cos 4x)+5(\cos 4x+\cos 2x)+10(\cos 2x+1)}{\cos 5x+5\cos 3x+10\cos x} $ $ =\frac{2\cos 5x\cos x+5.2\cos 3x,cos,x+10.2{{\cos }^{2}}x}{\cos 5x+5cos3x+10cosx} $ $ =\frac{2\cos x(\cos 5x+5\cos 3x+10\cos x)}{\cos 5x+5\cos 3x+10\cos x}=2\cos x $
BETA
