Trigonometric Identities Question 121
Question: If $ \sin \theta +\cos \theta =m $ and $ \sec \theta +cosec\theta =n $ , then $ n(m+1)(m-1)= $
[MP PET 1986]
Options:
A) m
B) n
C) 2m
D) 2n
Show Answer
Answer:
Correct Answer: C
Solution:
$ n(m^{2}-1)=(\sec \theta +cosec\theta ).2\sin \theta \cos \theta $ ( $ \because m^{2}=1+2\sin \theta \cos \theta $ ) $ =\frac{\sin \theta +\cos \theta }{\sin \theta .\cos \theta }.2\sin \theta \cos \theta =2m $ .
BETA
