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another math problem?

Given the following function, f(x)=x^3-6x^2+15, on the interval [-2.5, 5]

A. Determine the open interval(s) where f(x) is increasing.

B. Determine the open interval(s) where f(x) is decreasing.

C. Determine the extreme points and classify them as relative and/or absolute maximum(s) or minimum(s)

Thanks!

1 Answer

Relevance
  • 1 decade ago
    Favorite Answer

    f(x) = x^3 - 6x^2 + 15

    f ' (x) = 3x^2 - 12x

    equate f ' (x) to zero to get critical points

    3x^2 - 12x = 0

    => x(x - 4) = 0

    x = 0 and 4

    f(-2.5) = -125/8 - 6(25/4) + 15 = (120 - 125 - 300)/8 = -305/8 = -38.125

    f(0) = 15

    f(4) = 64 - 96 + 15 = -17

    f(5) = 125 - 150 + 15 = -10

    relative minimum is -38.125 and occurs at end point x = -2.5

    relative maximum is 15 and occurs at critical points x = 0

    C)

    now you can classify extreme points.

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