内容正文:
课时10立体几何的综合应用
D
C
B
P-ABCD
E
PA
BE
PC
P
E
DA
B
1-3
2
AC
AC
0
OE OB
EO PC
BE PC
∠BEO
△BEO
EO=L,B0=√2,BE=V5
cos∠BEO=
BE2+E02-B02V5
BE PC
5
2BE?EO
3
3
D
E
B
0
2
D
D
E
B
B
0
C
M
℃
D
B
W
DR
DA
P
M
B
D
n.DP=0,
nDA=0.
桑
n.CM
n⊥DP
吐
二
套
CM PD PA
CM
PD
PA
女
●
BE·DA
BE D.
C
M
E
B
D
A
W
B
A
B
E
C
B
24
A
B
y
E
C
上X
NN
W
文
ADI∥BCAB=BC=1AD=3
DE=PE=2
AD
PE⊥AD
BFI∥
PCD
AB⊥
PED
PAB
PCD
B
PD
S
SF,SC
SFHED.SF-ED-
ED//BC,ED =2BC
SFI∥BC,SF=BC
SFBC
BF//SC
BF丈
PCD
SCc
PCD
BFI∥
PCD
ZA
S
ED=2
AE=1
AE//BC,AE=BC
AECB
CEI∥AB
CE⊥
PAD
PE,EDC
PAD
CE⊥PE,CE⊥ED
PE⊥ED
A(0,-1,0,B(1,-1,0),C(1,0,0,D0,2,0),P0,0,2
PA=(0,-1,-2,PB=(1,-1,-2),PC=(1,0,-2),PD=(0,2,-2
m.PA=0
-y-2z=0
PAB
m=(x,y,z)
m.PB=0
x-y-2z=0
n.PC=0,
m=(0,-2,1
PCD
n=(a,b,c)
nPD=0,
a-2b=0
2b-2c=0
n=(21,1
V30
PAB
30
PCD
√30
30
E
B
M
E
D
-------->
A
B
Z个
P
E
D
C
A
B
0
P
E
B
C
A
0
D
B
☒
倒
a
业
4
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