What is the extreme f(x)=-7x^3+21x+4 ?

The extreme f(x)=-7x^3+21x+4 is Minimum(-1,-10),Maximum(1,18)

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extreme f(x)=-7x^3+21x+4

extreme

Minimum (- 1, - 10), Maximum (1, 18)

Solution steps

f^{'} (x) = - 21 x^{2} + 21

Find intervals:

Decreasing

: - \infty < x < - 1,

Increasing

: - 1 < x < 1,

Decreasing

: 1 < x < \infty

Plug

x = - 1

into

- 7 x^{3} + 21 x + 4 : - 10

Minimum (- 1, - 10)

Plug

x = 1

into

- 7 x^{3} + 21 x + 4 : 18

Maximum (1, 18)

Minimum (- 1, - 10), Maximum (1, 18)

What is the extreme f(x)=-7x^3+21x+4 ?
The extreme f(x)=-7x^3+21x+4 is Minimum(-1,-10),Maximum(1,18)