(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 |