٥륯åĥ
AEEC=ABBCADAC
ADAEACCE73
CE=9/4ˤʤޤ
ǼĤǧڤ9/4줺2.25ޤ
56ڡ 0:08:57 50445
EG
9/4ޤǤΤ2.25ޤǧΤ
ΤǤ礦

ǽϳѤʬäƤޤޤ
EAB˿EP򲼤ADC梤EPA73ʤΤǡADED73
AEED43ȤоǤ狼ϰϤʤȻפޤ
56ڡ 0:14:13 50446
鯤ο
ACD梤BADꡢ
AC:ADBA:BD
ޤѤʬ顢
AB:BDAE:ED
äơ
7DE+33:DE
򤤤ơDE9/4
//

56ڡ 0:17:40 50447
ߤ
ȤʤȤˤäƤϢϺǯ礳礳Ƥޤ
ޤˤϴγع⤤ΤǤ

ѷ£ŤŤ֤£þˣǤ뢪ţǡᣳ
ѷģäȻѷţģǤ棷ˤʤ롣
56ڡ 0:24:07 50448

ޥ뤵ΤŹҹԤäƤߤǤ
56ڡ 1:58:08 50449
ֿء׾ι
ĤΣդ椬ʬäΤǡ
56ڡ 5:32:49 50450
ˤ
Ѥʬդ椫顣
Ķļˡ 56ڡ 5:54:08 HomePage:ޤޤ50451
ϥ饮㡼ƥ
Ϥ褦ޤ
MATHEMATICAǤ
56ڡ 9:04:21 MAIL:tfuruya@aria.ocn.ne.jp 50453

BEĹACȸFȤ
BDE梤BAFǢBED=BFA=AEFʤΤ
AE=AF=3, CF=4 ʤΤBA:BC=3:4=AC:AD
äAD=73/4=21/4, DE=21/4-3=9/4 Ȥޤ
56ڡ 14:24:28 50454

BA:BC=3:4=AC:ADAD:AC
56ڡ 14:26:52 50455
Ȥ
ɸA(a,0),B(0,0),C(a,7)Ȥ
tan(CBA)=7/atan(2*ABE)=tan(CBA)=7/a
tan2ܳѤεդľEBη(=tan(ABE))ޤ
ľEBޤľAD:y=-a*(x-a)/7(1)
ȤθEޤAȤεΥ3ǻʿ
aޤޤ
ľBC:y=7*x/a(1)ȤθDޤ
aͤƻʿʬDA
AEMaxima

trigexpand(tan(2*a))$
part(solve([y=-a*(x-a)/7,y=rhs(part(solve(%=7/a,tan(a)),2))*x],[x,y]),1)$
num(factor((rhs(part(%o2,1))-a)^2+rhs(part(%o2,2))^2-9))$
factor(part(%,1)^2-(%-part(%,1))^2)$
part(solve([y=-a*(x-a)/7,y=7*x/a],[x,y]),1)$
sqrt(ev(factor((rhs(part(%o5,1))-a)^2+rhs(part(%o5,2))^2)
,part(solve(part(-%o4,2),a),2)))-3;9/4()
˭ԡ 56ڡ 17:56:17 MAIL:fttnm528@ybb.ne.jp 50456
ɥȥ
EAB˿򲼤Ƥ­PȤȢAPEȢCDAˤʤꡢޤ֤DE=PEDE򭡤Ȥȡ
:3=(+3):7
㼰򤤤ƭ=9/4
56ڡ 18:29:57 50457
Ȥ
ɸǤʤˡǤޤ
3ˡܤȤƺɸǤκǽβˡͤơ

ED=aȤCD=sqrt(49-(3+a)^2)
CAD梤CBA=sqrt(49-(3+a)^2):7=3+a:AB
AB=7*(3+a)/sqrt(49-(3+a)^2)
dzѤ2ʬ
3:a=7*(3+a)/sqrt(49-(3+a)^2):BD
BD=7*a*(3+a)/sqrt(49-(3+a)^2)/3
ABDǻʿ
AB^2=BD^2+AD^2
(7*(3+a)/sqrt(49-(3+a)^2))^2-((7*a*(3+a)/sqrt(49-(3+a)^2)/3)^2+(3+a)^2)
=(a+3)^2*(4*a-9)*(10*a+9)/((a-4)*(a+10))/9=0 a=ED=4/9()
˭ԡ 56ڡ 19:08:58 MAIL:fttnm528@ybb.ne.jp 50458
Ȥ
#50458
>3ˡܤȤƺɸǤκǽβˡͤơ
>(a+3)^2*(4*a-9)*(10*a+9)/((a-4)*(a+10))/9=0 a=ED=4/9()


3ˡܤȤƺɸǤκǽβˡȰ㤦Τͤ
=(a+3)^2*(4*a-9)*(10*a+9)/((a-4)*(a+10))/9=0 a=ED=9/4()

Ϸ׻̤ä褦ʡ

ɸA(b,a*b),B(0,0),ľBA:y=a*x,ľBD:y=-a*x
ľAD:y=(x-b)/a+a*b,ľAC:y=-(x-b)/a+a*b
ľADy=0Ȥx(1-a)*(1+a)*b
E((1-a)*(1+a)*b,0)AȤεΥ3ǻʿ
a^4*b^2+a^2*b^2-9=0(1)
ľBD,ACθC(-(a^2+1)*b/(a^2-1),(a^3+a)*b/(a^2-1))
AȤεΥ7ǻʿ
4*a^4*b^2+4*a^2*b^2-49*a^4+98*a^2-49=0
(1)ȤϢΩ
a=1/sqrt(7),b=21/2^(3/2)
ޤľBD,ADθD(-(a^2-1)*b/(a^2+1),(a^3-a)*b/(a^2+1))
a,bͤD,E
E(9/sqrt(2),0),D(63*sqrt(2)/16,-9*sqrt(14)/16)
ǻʿ
DE=sqrt((9/sqrt(2)-63*sqrt(2)/16)^2+(-9*sqrt(14)/16)^2)=9/4()
˭ԡ 56ڡ 21:30:21 MAIL:fttnm528@ybb.ne.jp 50459
Ȥ
#50456
ɸtanεդǤʤˡ

ɸB(0,0),BC=x,E(a,b)tan2ܳѤA(a,-2*a^2*b/((b-a)*(b+a)))
AE=3-2*a^2*b/((b-a)*(b+a))-b-3=0
b^3+3*b^2+a^2*b-3*a^2=0(1)
ľAC:y=((b-a)*(b+a)/(a*b)/2)*(x-a)-2*a^2*b/((b-a)*(b+a))
y=0Ȥx
(a*b^4+2*a^3*b^2+a^5)/(b^4-2*a^2*b^2+a^4)
C((a*b^4+2*a^3*b^2+a^5)/(b^4-2*a^2*b^2+a^4),0)
Aǻʿ
((a*b^4+2*a^3*b^2+a^5)/(b^4-2*a^2*b^2+a^4)-a)^2+(-2*a^2*b/((b-a)*(b+a)))^2-49
=-(7*b^4-2*a^2*b^3-14*a^2*b^2-2*a^4*b+7*a^4)
*(7*b^4+2*a^2*b^3-14*a^2*b^2+2*a^4*b+7*a^4)/((b-a)^4*(b+a)^4)
7*b^4-2*a^2*b^3-14*a^2*b^2-2*a^4*b+7*a^4=0 (1)ϢΩ
a=9*sqrt(7)/4,b=9/4
7*b^4+2*a^2*b^3-14*a^2*b^2+2*a^4*b+7*a^4=0 (1)ϢΩ
ŬϤʤED=Eyɸ=b=9/4()
˭ԡ 57ʶ 12:35:34 MAIL:fttnm528@ybb.ne.jp 50460
ե󥿥
פ֤Ǥ
ܱ蹥ξ6ǯ 57ʶ 23:15:01 50461
Ȥ
βˡޤǤμʬβˡǺû
Ȥʤ˳ڤˡ

EF=ED ꡡ3*(3+a)/7=a 7*a=9+3*a ED=a=9/4
˭ԡ 58ڡ 12:14:12 MAIL:fttnm528@ybb.ne.jp 50462
Ȥ
#50462

ߤޤˡڤơ!!

ED=aȤEʬBA˿򲼤­FȤ
(3+a)/7=EF/3 EF=3*(3+a)/7
EF=ED ꡡ3*(3+a)/7=a 7*a=9+3*a ED=a=9/4
˭ԡ 58ڡ 12:16:16 MAIL:fttnm528@ybb.ne.jp 50463
ޤ
̵ޤȳѤ2ʬǡ
ʽʻǤϤʤǤ͡ġ
somewhere in the world 59 1:11:47 50464
Ф
#50439 ïʤΤǤ

(x+y+z)^2=x^2+y^2+z^2+2xy+2yz+2zx
x2+y2+z2+xy+yz+zx=6
ѷ
1/2(x^2+y^2+z^2)+1/2(x+y+z)^2=6'
x+y+z=t魡'
x^2+y^2+z^2=12-t^2
Ȥʤ롣tλȭζʬʿ̤Ⱦ¤
(12-t^2)^(1/2)εθˤʤꡢ
餫˱ߤǤ롣ߤȸεΥlεȾ¤RȾ¤rȤ
r^2=R^2-l^2=12-t^2-t^2/3=12-4/3*t^2=4/3*(9-t^2)
äƸǰϤޤ줿ʬѤ4/3*(9-t^2)

ʬϤɤȤǤʤꤽ
511ʲС 4:12:01 50465

ѤʬDz򤤤ΤǤäƻϰϤǤä
DzؤʤΤ˺Ƥޤޤ
512ʿ 17:39:49 50466
ޤ
פ֤줿
512ʿ 22:33:40 50467