Mark the correct alternative in the following:

Function f(x) = 2x^{3} – 9x^{2} + 12x + 29 is monotonically decreasing when

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

Given:-

f(x) = 2x^{3} – 9x^{2} + 12x + 29

f’(x)=6(x-1)(x-2)

for decreasing function f’(x)<0

f’(x)<0

6(x-1)(x-2)<0

1<x<2

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