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For the function f(x)=2x3−21x2+36x−5f(x)=2x^3-21x^2+36x-5, which of the following statements are correct ?

A. x=2x=2 is a point of local maxima.

B. x=6x=6 is a point of local minima.

C. The local maximum value is 12.

D. The local maximum value is –94.

Choose the correct answer from the options given below:

Solution

✅ Correct Option: 4

f′(x)=6(x−1)(x−6)f'(x)=6(x-1)(x-6), so the critical points are x=1x=1 and x=6x=6.

The derivative changes from positive to negative at x=1x=1 (local maximum) and from negative to positive at x=6x=6 (local minimum), so A is false and B is true.

The local maximum value is f(1)=2−21+36−5=12f(1)=2-21+36-5=12, so C is true and D is false.

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