Trigonometric Identities Question 321
Question: If $ \tan \frac{\theta }{2}=t, $ then $ \frac{1-t^{2}}{1+t^{2}} $ is equal to
[Kerala (Engg.) 2002]
Options:
A) $ \cos \theta $
B) $ \sin \theta $
C) $ \sec \theta $
D) $ \cos 2\theta $
Show Answer
Answer:
Correct Answer: A
Solution:
$ \tan \frac{\theta }{2}=t\Rightarrow \frac{1-{{\tan }^{2}}\frac{\theta }{2}}{1+{{\tan }^{2}}\frac{\theta }{2}}=\cos \theta $ .
BETA
