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The points of local maxima and local minima of the f(x)=x3−6x2+9x+27f(x) = x^3 - 6x^2 + 9x + 27 are

Solution

✅ Correct Option: 1

f′(x)=3x2−12x+9=3(x−1)(x−3)f'(x)=3x^2-12x+9=3(x-1)(x-3). The sign of f′f' is positive, then negative, then positive, so f′f' changes +→−+\to- at x=1x=1 (local maximum) and −→+-\to+ at x=3x=3 (local minimum). Equivalently f′′(x)=6x−12f''(x)=6x-12 is negative at x=1x=1 and positive at x=3x=3.

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