MHT CET2019Evening ShiftMathematicsContinuity and DifferentiabilityActual
If the function f x = e k x − 1 tan k x 4 x 2 , x ≠ 0 16 , x = 0 is continuous at x = 0, then k = ….
Options
- A± 1 8
- B± 4
- C± 2
- D± 8
Correct answer
D. ± 8
Step-by-step solution
We have function, f x = e k x - 1 t a n k x 4 x 2 , x ≠ 0 16 , x = 0 is continuous at x = 0 ∴ l i m x → 0 f x = f 0 ⇒ l i m x → 0 e k x - 1 t a n k x 4 x 2 = 16 0 0 f o r m ⇒ l i m x → 0 e k x - 1 k x t a n k x k x × k 2 4 = 16 ⇒ k 2 4 = 16 ⇒ k 2 = 64 ⇒ k = ± 8