Trigonometric Identities Question 304
Question: If $ \cos 3\theta =\alpha \cos \theta +\beta {{\cos }^{3}}\theta , $ then $ (\alpha ,\beta )= $
Options:
A) $ (3,,4) $
B) $ (4,,3) $
C) $ (-3,,4) $
D) $ (3,,-4) $
Show Answer
Answer:
Correct Answer: C
Solution:
Given that $ \cos 3\theta =\alpha \cos \theta +\beta {{\cos }^{3}}\theta $ But $ \cos 3\theta =4{{\cos }^{3}}\theta -3\cos \theta $
Þ $ (\alpha ,\beta )=(-3,,4) $ .
BETA
