MHT CET2016MathematicsTrigonometric Equations
The solution of the equation sin 2 x + cos 2 x = 0 , where π < x < 2 π are
Options
- A7 π 8 , 11 π 8
- B9 π 8 ,   13 π 8
- C 11 π 8 ,   15 π 8
- D15 π 8 ,   19 π 8
Correct answer
C. 11 π 8 ,   15 π 8
Step-by-step solution
Given, sin 2 x + cos 2 x = 0 . Multiplying by 1 2 on both side, ∴ 1 2 sin 2 x + 1 2 cos 2 x = 0 ⇒ sin π 4 + 2 x = 0 ⇒ 2 x + π 4 = n π ⇒ x = 4 n - 1 π 8 ∴ x = 11 π 8 a n d 15 π 8