OD |
AD |
S△OBC |
S△ABC |
OE |
BE |
S△OAC |
S△BAC |
OF |
CF |
S△OAB |
S△CAB |
则
OD |
AD |
OE |
BE |
OF |
CF |
而
OD |
AD |
R−DM |
2R−DM |
R |
2R−DM |
R |
AD |
同理有,
OE |
BE |
R |
BE |
OF |
CF |
R |
CF |
代入①得,(1−
R |
AD |
R |
BE |
R |
CF |
所以
1 |
AD |
1 |
BE |
1 |
CF |
2 |
R |
1 |
AD |
1 |
BE |
1 |
CF |
2 |
R |
OD |
AD |
S△OBC |
S△ABC |
OE |
BE |
S△OAC |
S△BAC |
OF |
CF |
S△OAB |
S△CAB |
OD |
AD |
OE |
BE |
OF |
CF |
OD |
AD |
R−DM |
2R−DM |
R |
2R−DM |
R |
AD |
OE |
BE |
R |
BE |
OF |
CF |
R |
CF |
R |
AD |
R |
BE |
R |
CF |
1 |
AD |
1 |
BE |
1 |
CF |
2 |
R |