(1))DE=EP,(或DP),∠DEP(或∠EDP)=90°时,
设D(x1,m),E(x2,m),
∴(x1−x2) 2=m2,
由已知得CA方程:y=2x+2,
∴x1=
| m−2 |
| 2 |
| m |
| 2 |
CB方程:y=-
| 2 |
| 3 |
∴x2=-
| 3(m−2) |
| 2 |
| 3m |
| 2 |
∴得:4(m-2)2=m2,
解得:m1=
| 4 |
| 3 |
∴m=
| 4 |
| 3 |
(2)PD=PE,∠EPD=90°时,
则(
| x2−x1 |
| 2 |
∴( x2−x1)2=4m2,
∴4(m-2)2=4m2,
解得:m=1,
综上:当m=
| 4 |
| 3 |
| 4 |
| 3 |
| m−2 |
| 2 |
| m |
| 2 |
| 2 |
| 3 |
| 3(m−2) |
| 2 |
| 3m |
| 2 |
| 4 |
| 3 |
| 4 |
| 3 |
| x2−x1 |
| 2 |
| 4 |
| 3 |
| 4 |
| 3 |