| x2 |
| 4 |
| y2 |
| 3 |

∴a2=4,b2=3,可得c=
| a2-b2 |
所以椭圆的离心率e=
| c |
| a |
| 1 |
| 2 |
| a2 |
| c |
作出椭圆的右准线l如图,过M点作MN⊥l于N,
根据圆锥曲线的统一定义,得
| |MF| |
| |MN| |
| 1 |
| 2 |
∴2|MF|=|MN|,所以|MP|+2|MF|=|MP|+|MN|.
欲求|MP|+2|MF|的最小值,即求|MP|+|MN|的最小值,
过P(1,-1)作PN0⊥l于N0,交椭圆于M0,由平面几何知识可得,当动点M在椭圆上运动,与点M0重合时,|MP|+2|MF|取到最小值.
设M0(x0,-1),代入椭圆方程得
| x02 |
| 4 |
| (-1)2 |
| 3 |
2
| ||
| 3 |
∴使|MP|+2|MF|的值最小的点M的坐标为(
2
| ||
| 3 |
故答案为:(
2
| ||
| 3 |
