AD |
AB |
BE |
BC |
DM |
DE |
AD |
AB |
BE |
BC |
{ | xD=-2t+2 yD=-2t+1 |
{ | xE=-2t yE=2t-1 |
yE-yD |
xE-xD |
2t-1-(-2t+1) |
-2t-(-2t+2) |
DM |
DE |
{ | x=2(1-2t) y=(1-2t)2 |
x2 |
4 |
OD |
OA |
AD |
OA |
AB |
OA |
OB |
OA |
OA |
OB |
OE |
OB |
BE |
OB |
BC |
OB |
OC |
OB |
OB |
OC |
OM |
OD |
DM |
OD |
DE |
OD |
OE |
OD |
OD |
OE |
OA |
OB |
OC |
OA |
OB |
OC |
{ | x=(1-t2)?2+2(1-t)t?0+t2?(-2)=2(1-2t) y=(1-t)2?1+2(1-t)t?(-1)+t2?1=(1-2t)2 |