JEE Advanced2016MathematicsLimitsActual
Let α , β ∈ R be such that lim x → 0 ⁡ x 2 sin ⁡ β x α x - sin ⁡ x = 1 . Then 6 α + β equals
Correct answer
7
Step-by-step solution
If α ≠ 1 , then lim x → 0 x sin β x α x - sin x x = 0 ∴ α = 1 ⇒ lim x → 0 β x 3 sin β x β x x 3 x - sin x x 3 = β 1 6 Using, lim x → 0 x - sinx x 3 = 1 6  & lim x → 0 sinx x = 1 ⇒ 6 β = 1 ⇒ β = 1 6 ⇒ 6 α + β = 7