JEE Main2014MathematicsContinuity and DifferentiabilityActual
If the function f x = 2 + cos x - 1 π - x 2 , x ≠ π k , x = π is continuous at x = π , then k equals
Options
- A1 4
- B0
- C2
- D1 2
Correct answer
A. 1 4
Step-by-step solution
Given f x = 2 + cos x - 1 π - x 2 , x ≠ π k , x = π is continuous at x = π Hence, f π = lim x → π f x ⇒   k = lim x → π 2 + cos x - 1 π - x 2 Consider L . H . L . = lim x → π - 2 + cos x - 1 π - x 2 lim h → 0 2 + cos ( π - h ) - 1 π - π - h 2 Also, cos π - h = - cos   h ⇒   k = lim h → 0 2 - cos h - 1 h 2 ⇒   k = lim h → 0 2 - cos h - 1 h 2 × 2 - cos h + 1 2 - co