BITSAT2017MathematicsContinuity and DifferentiabilityActual
Consider the greatest integer function, defined by f ( x ) = [ x ] , 0 ≤ x < 2 . Then
Options
- Af is derivable at x = 1
- Bf is not derivable at x = 1
- Cf is derivable at x = 2
- DNone of these
Correct answer
B. f is not derivable at x = 1
Step-by-step solution
The given function is f x = 0 , 0 ≤ x < 1 1 , 1 ≤ x < 2 Now, LHD = lim x → 1 - f ( x ) - f ( 1 ) x - 1 = lim x → 1 - 0 - 1 x - 1 Which does not exist ∴   f is not derivable at x = 1 .