(1))DE=EP,(或DP),∠DEP(或∠EDP)=90°時,
設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°時,
則(
x2?x1 |
2 |
∴( x2?x1)2=4m2,
∴4(m-2)2=4m2,
解得:m=1,
綜上:當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 |