Trigonometric Identities Question 331
Question: $ \frac{\sin 3A-\cos ( \frac{\pi }{2}-A )}{\cos A+\cos (\pi +3A)}= $
Options:
A) $ \tan A $
B) $ \cot A $
C) $ \tan 2A $
D) $ \cot 2A $
Show Answer
Answer:
Correct Answer: D
Solution:
$ \frac{\sin 3A-\cos ( \frac{\pi }{2}-A )}{\cos A+\cos (\pi +3A)}=\frac{\sin 3A-\sin A}{\cos A-\cos 3A} $ = $ \frac{2\cos 2A\sin A}{2\sin 2A\sin A}=\frac{\cos 2A}{\sin 2A}=\cot 2A $ .
BETA
