MHT CET202013 Oct 2020Morning ShiftMathematicsContinuity and DifferentiabilityActual
If the function f(x)= 1- 2 x+ 2 x 1+ 2 x+ 2 x if x 2 = k if x= 2 is continuous at x= 2 , then k =
Options
- A2
- B1
- C0
- D-1
Correct answer
D. -1
Step-by-step solution
aligned _ x 2 f(x)=& _ x 2 1- 2 x+ 2 x 1+ 2 x+ 2 x =& _ x 2 (1+ 2 x)- 2 x (1+ 2 x)+ 2 x = _ x 2 2 ² x-2 x x x+2 x x =& _ x 2 2 x( x- x) 2 x( x+ x) = _ x 2 x- x x+ x = 0-1 0+1 =-1 aligned Since f(x) is continuous at x= 2 , we get k=-1