-
(2,3)=(-1.2) 2/14-315
= (1+â3,5 ? AC = (1, (3) +12+12-13+ || 22
â 14
第1ç« å¹³é¢äžã®ãã¯ãã«
(2) B
ãããšãOA22=
ita
a+22
A.A21 BB2CiCaã®äžç¹ããããããL,M,Nããããš
c
atate
4
ãšãªãäžèŽããã
STEP B
*52 â A=60°, AB=8, AC = 5 ã§ãã â³ABCã®å
å¿ãâ
ãšããã AB=6.
AC=C ãšãããšã, Ai ã6,ããçšããŠè¡šãã
53 â³ABCã®èŸºBC, CA, ABã®äžç¹ããããã A1, B1, C1 ãšã, å¹³é¢äžã®ä»»
æã®ç¹0ã«å¯Ÿã, ç·å OA, OB, OCã®äžç¹ããããã A2, B2, C2 ãšããã
ç·åAjAz, BiB2, CC2 ã®äžç¹ã¯äžèŽããããšã蚌æããã
*54 â³ABC ã®éå¿ãGãšãããšã,ãã®å¹³é¢äžã®ä»»æã®ç¹Pã«å¯ŸããŠ,çåŒ
AP+BP-2CP=3GC ãæãç«ã€ããšã蚌æããã
â 55 â³ABCãšç¹Pã«å¯ŸããŠ,次ã®çåŒãæãç«ã€ãšã,ç¹Pã®äœçœ®ãããã
*(1) PA+PB+PC=AB
*(2) AP+BP+CP=0
(3) PA+PC=AC
äŸé¡ 5 â³ABCãšç¹Pã«å¯ŸããŠ, çåŒ 6AP+3BP+2CP=0ãæãç«ã€ãš
ã, ç¹Pã¯ã©ã®ãããªäœçœ®ã«ãããã
æéçåŒããPã®äœçœ®ãã¯ãã«ã衚ãåŒãå°ãã ãã®åŒããPãããç·åã®å
åç¹ã§ãã
ããšãªã©ã倿ããã è§£çã§ã¯Aã«é¢ããäœçœ®ãã¯ãã«ãèããŠããã
[è§£ç AB=1, AC=c, AP= ãšããã
65+3(-6)+2(-2)=6
36+2c5x3+2c5x36+2c
11 11
çåŒãã
ãã£ãŠ
5
11
2+3
ãããã£ãŠ, 蟺BC ã2:3ã«å
åããç¹ãDãšãããš,
ç¹Pã¯ç·åAD ã 5:6 ã«å
åããç¹
B2-
D
C
12-
4STEPæ°åŠC ãã¯ãã«
(+1)+(+1)
+1/+1-1)
=0
[å¥ AB=6,AC-
ãšãããš
AD=2AB+ AC
1+2
BE=AE-AB
=-6
CF-AF-AC
ãã£ãŠ
JALAS In ek
AD+BE+CF
(6+1)+(-6)+(-)
=(1+1)+(+1)=0
51 A, B, C,D,E,F ã®äœçœ®ãã¯ãã«ã,ãã
ããa, b,c,d,e,ãšã,L,M,N,P,Q,
Rã®äœçœ®ãã¯ãã«ã, ãããã1,m,n,p.g.
ãšããããã®ãšã
_a+6
2
m=
2
ate
*=2-50 a
p=d+ež q=e+³ž 7 = 7+a
2
â³LNQã®éå¿Gã®äœçœ®ãã¯ãã«ãg ãšãããš
i+n+g
g=-
3
1/a+b c+d
=
52èšç»
å
å¿ã¯è§ã®äºçåç·ã®äº€ç¹ã§ããããã
äºçåç·ã®æ§è³ªãå©çšã§ããã
LAã®äºçåç·ãšèŸºBCã®äº€ç¹ãDãšããã
BD:DC=AB: AC, AI ID=BA:80
ããã
â Aã®äºçåç·ãšèŸºBC
ã®äº€ç¹ãDãšãããš
BD: DC=AB:
ãã£ãŠ
=8:5
AC
AD=5AB+8AC
8+5
50+8c
OL-OA+OA
b + c à IN
2 2
56 æé
**
(2) ABCã®é¢ç©ãSãšL
â³PCA, â³PABã®é¢ç©ã
(1) AB=6.
AC=c,
AP=p
c+a b
çåŒãã5p+4p-b)+3
OM=
OB,+OBâ
ããã«
[30
p=4b+3c
-
a+b
D
OC+OC2
ON=-
13
ãŸã, â³ABCã«ãããŠãäœåŒŠå®çã«ãã
BC" =82 +52-2Ã8Ã5cos60=49
BC 0 ã§ãããã
ãã£ãŠ
BC=7
8x7
BD BO=13
BIã¯â Bã®äºçåç·ã§ãããã
OL=OMON ãšãªãããã L., MNã¯äžèŽ
ãããããªãã¡ãç·åA1A2. B,B2 CC2ã®äž
ç¹ã¯äžèŽãã ã
54 A, B, C. G.Pã®äœçœ®ãã¯ãã«ãããã
a,b,c.g, ãšããã
12
=1/2x4+3
7
745+=
=123+
ãããã£ãŠ,蟺BCã3:
ãããšãç¹Pã¯ç·åAD
ããã
(2) â³ABCã®é¢ç©ã S
ãšãã
ãš
APBC=12
APCA = AADC
8x7
AI: ID=BA BD=8:
-=13:7
ç¹Gã¯â³ABCã®éå¿ã§ãããã
13
a+b+c
ããã«
AI=1347 AD=0x50+8
13
ãããã£ãŠ
53 OA=a, OB=1,
巊蟺å³èŸº
=AP+BP-2CP-3GC
=(-a)+(-6)-2p-c)-3(c-g)
= -a+b+c)+3g
5091
3x +
=-(a+b+c)+3x_
OC=c ãšãããš
OB+OC
OAâ =
B2
2
G
b+c
2
ãã£ãŠ å·ŠèŸº=å³èŸº
A02
Aâ
OC+OA
OBâ =
=(a+6+2)+(a+6+2 = d
55AB=6. AC=c, AP= ãšããã
-P+(b-p)+(c-p)=
*56 â³ABCãšç¹Pã«å¯ŸããŠ, çåŒ 5AP+4BP+3CP=0 ãæãç«ã£ãŠããã
(1) ç¹Pã®äœçœ®ãããã
(2)â³PBC: â³PCA: â³PAB ãæ±ããã
ã»ã³ã
52è§ã®äºçåç·ã®æ§è³ªãå©çšã â³ABCã«ãããŠ,â Aã®äºçåç·ãšèŸºBCã®äº€ç¹ãDãš
ãããš BD DC=AB: AC
53
ç·å A1 A2, BiB2, CiC2 ã®åäžç¹ã®äœçœ®ãã¯ãã«ãäžèŽããããšã瀺ãã
ã°åºèŸºã®é·ãã®æ¯ã«çããã
56 (2)äžè§åœ¢ã®é¢ç©ã®æ¯ã¯ãåºèŸºã®é·ããçãããã°é«ãã®æ¯ã«çãã,é«ããçããã
3 2
¹(a+b+c+d+e+1)
â³MPR ã®éå¿ã®äœçœ®ãã¯ãã«ããšãããš
_mtptr
g="
1(b+c d+e +a\
"32"
=(a+b+c+d+e+7)
g=gãšãªããã,GãšGã¯äžèŽããã
6-3-5-(-6)
APAB=12AABD
APBC: APCA
ãã£ãŠ
c+a
2
1çåŒãã
ãã£ãŠ
OA+OB
OC=
a+b
ãããã£ãŠãç¹Pã¯èŸº ACã12ã«å
åããç¹
ã§ããã
OA
ãŸã 02= 2 =2
2) çåŒãã
P+(-b)+(p-2)=0
57 AB=OB-OA
=b-a
AP=OP-0A
=(3a-26)
=2a-26
=-26-2
ãã£ãŠAP=
ããã«ãç¹Pã¯
a0, b
æ¡ä»¶ããçŽ
OB b
ãã£ãŠ
0B2=
b= b+c
22
58 (1) OB=4-
OC
C
OC-22
3)çåŒãã
ãããã£ãŠãç¹Pã¯â³ABCã®éå¿ã§ããã
-p+(c-p)=c
ãã£ãŠã3ç¹
(2) AC=OC-
ããã§, ç·åA1A, B, B2, CiC2 ã®äžç¹ãã ã
ããã L, M, Nãšãããš
ãã£ãŠ
p=o
=(24+
ãããã£ãŠ, ç¹Pã¯AãšäžèŽããã
=400+