Mathematics

Mathematics

Problem

Let f(x)=x3−6x2+9xf(x)=x^{3}-6x^{2}+9x for 0≤x≤50\le x \le 5. Determine the xx-coordinate at which ff attains its absolute maximum on the interval [0,5][0,5]. a) x=1x=1 b) x=4x=4 c) x=5x=5 d) x=3x=3
Intuitive explanation

The key is to remember that absolute extrema on a closed interval occur either at critical points (where f′(x)=0f'(x)=0) or at the endpoints. Find where the derivative equals zero by factoring, then evaluate ff at those critical points and at x=0x=0 and x=5x=5 to compare. Whichever location gives the largest output is your answer.

Intuitive explanation

The key is to remember that absolute extrema on a closed interval occur either at critical points (where f′(x)=0f'(x)=0) or at the endpoints. Find where the derivative equals zero by factoring, then evaluate ff at those critical points and at x=0x=0 and x=5x=5 to compare. Whichever location gives the largest output is your answer.

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