NTA Abhyas JEE Main2020MathematicsInverse Trigonometric FunctionsPractice
The complete solution set of the inequality cos - 1 ( cos 4 ) > 3 x 2 - 4 x is
Options
- A0 , 2 + 6 π - 8 3
- B2 - 6 π - 8 3 , 0
- C( - 2, 2 )
- D2 - 6 π - 8 3 , 2 + 6 π - 8 3
Correct answer
D. 2 - 6 π - 8 3 , 2 + 6 π - 8 3
Step-by-step solution
As, cos - 1 ( cos 4 ) = cos - 1 cos 2 π - 4 = 2 π - 4 ⇒ 2 π - 4 > 3 x 2 - 4 x ⇒ 3 x 2 - 4 x - 2 π - 4 < 0 ⇒ 2 - 6 π - 8 3 < x < 2 + 6 π - 8 3