Trigonometric Identities Question 351
Question: If $ \sin A=\sin B $ and $ \cos A=\cos B, $ then
[EAMCET 1994]
Options:
A) $ \sin \frac{A-B}{2}=0 $
B) $ \sin \frac{A+B}{2}=0 $
C) $ \cos \frac{A-B}{2}=0 $
D) $ \cos (A+B)=0 $
Show Answer
Answer:
Correct Answer: A
Solution:
We have $ \sin A=\sin B $ and $ \cos A=\cos B $ $ \frac{\sin A}{\sin B}=\frac{\cos A}{\cos B},\Rightarrow \sin A,\cos B-\cos A,\sin B=0 $
$ \Rightarrow \sin ,(A-B)=0 $ Hence, $ \sin ,( \frac{A-B}{2} )=0. $
BETA
