| x2 |
| 16 |
| y2 |
| 9 |
∴椭圆与x正半轴交于点A(4,0),与y正半轴的交于点B(0,3),
∵P是椭圆上任一个动点,设点P(4cosθ,3sinθ)(θ∈[0,2π])
∴点P到直线AB:3x+4y-12=0的距离为
d=
| |12cosθ+12sinθ−12| | ||
|
| 12 |
| 5 |
| 2 |
| π |
| 4 |
由此可得:当θ=
| 5π |
| 4 |
| 12 |
| 5 |
| 2 |
∴△PAB面积的最大值为S=
| 1 |
| 2 |
| 2 |
| x2 |
| 16 |
| y2 |
| 9 |
| x2 |
| 16 |
| y2 |
| 9 |
| |12cosθ+12sinθ−12| | ||
|
| 12 |
| 5 |
| 2 |
| π |
| 4 |
| 5π |
| 4 |
| 12 |
| 5 |
| 2 |
| 1 |
| 2 |
| 2 |