Mark the correct alternative in the following:

Let f(x) = x3 – 6x2 + 15x + 3. Then,

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)

(ii)If f(x) is strictly increasing function on interval [a, b], then f-1 exist and it is also a strictly increasing function

Given:- f(x) = x3 – 6x2 + 15x + 3


Therefore f’(x) will increasing

Also f-1(x) is possible

Therefore f(x) is invertible function.