Question
Question: The solution set of the inequality \(\log_{(\cos x)^{2}}{}\) (3 – 2x) \<\(\log_{(\cos x)^{2}}{}\) (...
The solution set of the inequality
log(cosx)2 (3 – 2x) <log(cosx)2 (2x – 1) is –
A
(21,1)
B
(– ¥, 1)
C
(21,3)
D
(1, ¥) – 2nπ"nÎN
Answer
(21,1)
Explanation
Solution
\ 3 – 2x > 0 & 2x – 1> 0 for log to exist
x < 3/2 & x > 1/2 \ x Î (21,23) ...(1)
Now 0 < cos2x < 1
Take antilog
3 – 2x > 2x – 1 ̃ 4x < 1 ̃ x < 1 ...(2)
From (1) & (2) x Î(21,1)