A few days ago
chessmaster2000

Calculus help needed?

Let F(x) = x^4 – 8x^2 +24 on the interval [-3,3]

(a) Find all relative Extrema of the Function.

(b) Find all the absolute extrema of the Function.

Top 1 Answers
A few days ago
Truly W

Favorite Answer

F(x) = x^4 – 8x^2 +24 on the interval [-3,3]

The derivative of F is F'(x) = 4x^3 -16x = 4x * (x^2 -4)

For relative extrema, check the value of F where F’ = 0 on the interval [-3,3]. If allowed, also check F at the endpoints if your definition of RELATIVE extrema includes values at the endpoints.

F’ = 0 when 4x=0 ===> x=0

F’ = 0 when x^2 = 4 ===> x=+/-2

Relative extrema:

===============

F(0) = 0 – 0 + 24 = 24

F(2) = 16 – 32 + 24 = 8

F(-2) = 16 – 32 + 24 = 8

F(3) = 81 – 72 + 24 = 33 *** if the endpoints are allowed ***

F(-3) = 81 – 72 + 24 = 33 *** if the endpoints are allowed ***

Absolute extrema

==============

Absolute extrema are found by taking the relative extrema and the values at the end points.

F(2) and F(-2) are the absolute minimum value of this function with a value of 8.

F(-3) and F(3) are the absolute maximum value of this function on this interval with a value of 33.

0