Mathematics

Mathematics

Problem

Consider the function p(x)=x4−4x3p(x)=x^{4}-4x^{3} defined on the closed interval [−1,5][-1,5]. Which ordered pair gives both the xx-coordinate and the corresponding value of the absolute minimum of pp on [−1,5][-1,5]? a) (0,0)(0,0) b) (2,−16)(2,-16) c) (3,−27)(3,-27) d) (4,0)(4,0)
Intuitive explanation

To find an absolute minimum on a closed interval, you need to check three types of locations: critical points (where p′(x)=0p'(x) = 0), points where the derivative doesn't exist, and the endpoints. The key insight is that the absolute minimum must occur at one of these candidates—so evaluate p(x)p(x) at each and compare. Start by finding where p′(x)=0p'(x) = 0, then systematically test all candidates to identify which gives the smallest value.

Intuitive explanation

To find an absolute minimum on a closed interval, you need to check three types of locations: critical points (where p′(x)=0p'(x) = 0), points where the derivative doesn't exist, and the endpoints. The key insight is that the absolute minimum must occur at one of these candidates—so evaluate p(x)p(x) at each and compare. Start by finding where p′(x)=0p'(x) = 0, then systematically test all candidates to identify which gives the smallest value.

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