46点D,E,F の位置ベクトルを,それぞれd,
->
e,
芋とすると
1.
e=
b+2c 11+
→
2->
=
2+1
3.
à= a+b
==
←
7=c+3 = 17+ 3/2
f=
57
->>
(1) AC=c-a
a
2.
(2) BE = e− b = ( 1½ + ½² ² ) − b = −2+2
2
b+
BE=BC= (-6)=-6+
→
3
b+
→
2-3
(3) FA = à −7 ± à− ( 1 c + 2 a) = 1½ 179–10
[別解
-
=a
c+ a=
4
->
-
1-
4
FA-1CA=120-2=1/- 1/
->
4
(4) CD = d − c = ( 1½ à + 1½ 1 ) − c = 1½ a +
e- -a
2
C:
a+
C
74
C
(5) AE = − à = (½ + ½ ½)-à = −à+1/3+}
→
3
a=
a+
(6) DF = 7-d=(1+2)-(½ + ½ 6)
c+
1
***
+
C
