Mark the correct alternative in the following:

Let f(x) = x^{3} – 6x^{2} + 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) = x^{3} – 6x^{2} + 15x + 3

=3x^{2}-12x+15=f’(x)

Therefore f’(x) will increasing

Also f^{-1}(x) is possible

Therefore f(x) is invertible function.

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