Question

国外一道简单的数学函数题，最好写在纸上拍照方便一点。感激不尽！！

需要画个图，然乎描述一下每个步骤。 找这几个点我会，不过搞不清楚弧度要划多大。谢谢了！

Answer 1

x -> -∞: f(x) -> x^5, f(x) -> -∞

x -> +∞: f(x) -> x^5, f(x) -> +∞

It's easy to see f(x) intersects the x-axis at (-3, 0), (-1, 0), (1, 0), and (2, 0)

(1) x < -3: x + 3 < 0, , x + 1 < 0, x - 2 < 0, x - 1 < 0, f(x) is the product of 5 negative numbers, and is negative

(2) -3 < x < -1: x + 3 > 0, , x + 1 < 0, x - 1 < 0, x - 2 < 0, f(x) is the product of 4 negative and a postitive numbers, and is positive
(3) -1 < x < 1: x + 3 > 0, , x + 1 > 0, x - 1 < 0, x - 2 < 0, f(x) is the product of 3 negative and 2 postitive numbers, and is negative
(4) 1 < x < 2: x + 3 > 0, , x + 1 > 0, x - 1 < 0, x - 2 < 0, f(x) is the product of 1 negative and 4 postitive numbers, and is negative

(5x>2: x + 3 > 0, , x + 1 > 0, x - 1 > 0, x - 2 > 0, f(x) is the product of 5 postitive numbers, and is positive

追问

请问那个曲线你是怎么确定画多大呢？那几个点我知道。谢谢

追答

要求导数，算各个区间的极值