Trigonometric Identities Question 10
Question: The value of $ \cos 15{}^\circ -\sin 15{}^\circ $ is equal to
[MNR 1975; MP PET 1994, 2002]
Options:
A) $ \frac{1}{\sqrt{2}} $
B) $ \frac{1}{2} $
C) $ -\frac{1}{\sqrt{2}} $
D) 0
Show Answer
Answer:
Correct Answer: A
Solution:
$ \cos 15^{o}-\sin 15^{o}=\sqrt{2},.\cos ,(45^{o}+15^{o})=\sqrt{2},.,\cos 60^{o} $ $ =\sqrt{2},.\frac{1}{2}=\frac{1}{\sqrt{2}} $ .
BETA
