Trigonometric Identities Question 142
Question: The value of $ \cos A-\sin A $ when $ A=\frac{5\pi }{4}, $ is
[MP PET 1990]
Options:
A) $ \sqrt{2} $
B) $ \frac{1}{\sqrt{2}} $
C) 0
D) 1
Show Answer
Answer:
Correct Answer: C
Solution:
$ \cos A-\sin A=\cos \frac{5\pi }{4}-\sin \frac{5\pi }{4},( \because A=\frac{5\pi }{4} ) $ $ =-\cos \frac{\pi }{4}+\sin \frac{\pi }{4}=-\frac{1}{\sqrt{2}}+\frac{1}{\sqrt{2}}=0 $ .
BETA
