| 1 |
| x |
∴函数f(x)的定义域为(0,+∞),
f′(x)=1-
| 1 |
| x2 |
| a |
| x |
| x2+ax-1 |
| x2 |
设函数f(x)在点(x0,y0)处的切线的斜率为2,
则
| ||
|
即
| x | 20 |
欲使该方程在x∈(0,+∞)内有且仅有一根,
应满足
|
(Ⅱ)g(x)=3x+
| 1 |
| x |
g′(x)=3-
| 1 |
| x2 |
| 2 |
| x |
| 3x2+2x-1 |
| x2 |
| 1 |
| 3 |
g'(x)<0,解得0<x<
| 1 |
| 3 |
所以函数g(x)的单调递增区间为(
| 1 |
| 3 |
| 1 |
| 3 |
所以函数有极小值g(
| 1 |
| 3 |
| 1 |
| x |
| 1 |
| x |
| 1 |
| x2 |
| a |
| x |
| x2+ax-1 |
| x2 |
| ||
|
| x | 20 |
|
| 1 |
| x |
| 1 |
| x2 |
| 2 |
| x |
| 3x2+2x-1 |
| x2 |
| 1 |
| 3 |
| 1 |
| 3 |
| 1 |
| 3 |
| 1 |
| 3 |
| 1 |
| 3 |