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Determine the location and value of the absolute extreme values of f on the given interval, if they exist. f(x)=x3−63x2 on [−21,63]

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Answer:

  • minima: (-21, -37044) and (42, -37044)
  • maxima: (0, 0) and (63, 0)

Explanation:

You want the absolute extreme values of f(x) = x³ -63x² on the interval [-21, 63].

Extremes

The absolute extremes will be located at the ends of the interval and/or at places within the interval where the derivative is zero.

Derivative

The derivative of f(x) is ...

f'(x) = 3x² -126x

This is zero when its factors are zero.

f'(x) = 0 = 3x(x -42)

x = {0, 42} . . . . . . . . . within the interval [-21, 63]

Function values

The attachment shows the function values at these points and at the ends of the interval. It tells us the minima are located at x=-21 and x=42. The maxima are located at x=0 and x=63. Their values are -37044 and 0, respectively.

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Additional comment

These are absolute extrema in the interval because no other values are larger than these maxima or smaller than the minima.

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Determine the location and value of the absolute extreme values of f on the given-example-1
User Jorin
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