NTA Abhyas JEE Main2020MathematicsTrigonometric EquationsPractice
The number of solutions to the equation 2 e sin x - 3 - e 2 sin x = e sin x - e 2 sin x - 1 in 0,2 π is
Options
- A0
- B2
- C4
- D3
Correct answer
B. 2
Step-by-step solution
Putting e sin x = t , we get, 2 t - 3 - t 2 = t - t 2 - 1 t 2 - 2 t + 3 = t 2 - t + 1 t 2 - 2 t + 3 > 0 , ∀ t ∈ R a n d t 2 - t + 1 > 0 , ∀ t ∈ R a s t h e i r d i s c r i m i n a n t < 0 ⇒ t 2 - 2 t + 3 = t 2 - t + 1 ⇒ t = 2 ⇒ e sin x = 2 ⇒ sin x = ln 2 ∈ 0,1 Hence, from the graph, we get, in 0,2 π there are two solutions