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 |