What is the extreme f(x)=-7x^3+21x+5 ?

The extreme f(x)=-7x^3+21x+5 is Minimum(-1,-9),Maximum(1,19)

English

Español

Português

Français

Deutsch

Italiano

Русский

中文(简体)

한국어

日本語

Tiếng Việt

עברית

العربية

extreme f(x)=-7x^3+21x+5

extreme

Minimum (- 1, - 9), Maximum (1, 19)

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 + 5 : - 9

Minimum (- 1, - 9)

Plug

x = 1

into

- 7 x^{3} + 21 x + 5 : 19

Maximum (1, 19)

Minimum (- 1, - 9), Maximum (1, 19)

What is the extreme f(x)=-7x^3+21x+5 ?
The extreme f(x)=-7x^3+21x+5 is Minimum(-1,-9),Maximum(1,19)