Mark the correct A. k ϵ (2, ∞)

B. kϵ (–∞, 2)

C. k ϵ (4, ∞)

D. kϵ (–∞, 4)

Formula:- (i) The necessary and sufficient condition for differentiable function defined on (a,b) to be strictly increasing on (a, b) is that f’(x)>0 for all x(a,b)

Given:-

f(x) = x² – kx + 5

For increasing function f’(x)>o

2x-k>0

K<2x

Putting x=2

K<4

kϵ (–∞, 4)