■サマーヴィルの等面四面体(その564)
【1】F6 in F5
△6を
P0(m√(1/2),0,m√(1/2),m,m√3,h)
P1(0,0,0,0,0,0)
P2(0,0,0,0,0,6h)
P3(m√2,m√3,0,0,0,5h)
P4(m√8,0,0,0,0,4h)
P5(m√(9/2),0,m√(9/2),0,0,3h)
P6(m√2,0,m√2,2m,0,2h)
としてみる.
P0P1^2=5m^2+h^2
P0P2^2=5m^2+25h^2
P0P3^2=8m^2+16h^2
P0P4^2=9m^2+9h^2
P0P5^2=8m^2+4h^2
P0P6^2=5m^2+h^2
P1P2^2=36h^2
P1P3^2=5m^2+25h^2
P1P4^2=8m^2+16h^2
P1P5^2=9m^2+9h^2
P1P6^2=8m^2+4h^2
P2P3^2=5m^2+h^2
P2P4^2=8m^2+4h^2
P2P5^2=9m^2+9h^2
P2P6^2=8m^2+16h^2
P3P4^2=5m^2+h^2
P3P5^2=8m^2+4h^2
P3P6^2=9m^2+9h^2
P4P5^2=5m^2+h^2
P4P6^2=8m^2+4h^2
P5P6^2=5m^2+h^2
5m^2+h^2(6)<5m^2+25h^2(2)
8m^2+4h^2(5)<8m^2+16h^2(3)
9m^2+9h^2(4)
36h^2(1)
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P0を外すと,等間隔ではなくなる点に注意して
P1P2^2=36h^2
P1P3^2=5m^2+25h^2
P1P4^2=8m^2+16h^2
P1P5^2=9m^2+9h^2
P1P6^2=8m^2+4h^2
P2P3^2=5m^2+h^2
P2P4^2=8m^2+4h^2
P2P5^2=9m^2+9h^2
P2P6^2=8m^2+16h^2
P3P4^2=5m^2+h^2
P3P5^2=8m^2+4h^2
P3P6^2=9m^2+9h^2
P4P5^2=5m^2+h^2
P4P6^2=8m^2+4h^2
P5P6^2=5m^2+h^2
36h^2(1)=5m^2+h^2(4)<5m^2+25h^2(1)
8m^2+4h^2(4)<8m^2+16h^2(2)
9m^2+9h^2(3)
36h^2(1)
F6は
P1P2=P2P3=P3P4=P4P5=P5P6=√6
P1P3=P2P4=P3P5=P4P6=√10
P1P4=P2P5=P3P6=√12
P1P5=P2P6=√12
P1P6=√10
であるから,
36h^2=5m^2+h^2=6,8m^2+4h^2=10
9m^2+9h^2=12,8m^2+16h^2=12,
5m^2+25h^2=10,m^2=7h^2
h^2=1/6,m^2=7/6
===================================
また,
P1(0,0,0,0,0,0)
P2(0,0,0,0,0,6h)
P3(m√2,m√3,0,0,0,5h)
P4(m√8,0,0,0,0,4h)
P5(m√(9/2),0,m√(9/2),0,0,3h)
P6(m√2,0,m√2,2m,0,2h)
のQ(x,y,z,w,v)がF5を形成すればよいのであるが,
P2P3^2=5m^2
P2P4^2=8m^2
P2P5^2=9m^2
P2P6^2=8m^2
P3P4^2=5m^2
P3P5^2=8m^2
P3P6^2=9m^2
P4P5^2=5m^2
P4P6^2=8m^2
P5P6^2=5m^2
===================================
【2】G6 in G5
次に外すとなったら,P6だろうか? この場合も等間隔ではなくなる点に注意して
P1P2^2=36h^2
P1P3^2=5m^2+25h^2
P1P4^2=8m^2+16h^2
P1P5^2=9m^2+9h^2
P2P3^2=5m^2+h^2
P2P4^2=8m^2+4h^2
P2P5^2=9m^2+9h^2
P3P4^2=5m^2+h^2
P3P5^2=8m^2+4h^2
P4P5^2=5m^2+h^2
36h^2(1)=5m^2+h^2(3)<5m^2+25h^2(1)=
8m^2+4h^2(2)<8m^2+16h^2(1)=
9m^2+9h^2(2)
G6は
P2P3=P3P4=P4P5=P5P6=√6
P2P4=P3P5=P4P6=√10
P2P5=P3P6=√12
P2P6=√12
であるから,
36h^2=5m^2+h^2=6,5m^2+25h^2=8m^2+4h^2=10
9m^2+9h^2=8m^2+16h^2=12,
h^2=1/6,m^2=7/6はこれらを満たす.
===================================
また,
P1(0,0,0,0,0,0)
P2(0,0,0,0,0,6h)
P3(m√2,m√3,0,0,0,5h)
P4(m√8,0,0,0,0,4h)
P5(m√(9/2),0,m√(9/2),0,0,3h)
のQ(x,y,z,w,v)がF5を形成すればよいのであるが,
P2P3^2=5m^2
P2P4^2=8m^2
P2P5^2=9m^2
P3P4^2=5m^2
P3P5^2=8m^2
P4P5^2=5m^2
===================================
【3】H6 in H5
次に外すとなったら,P5だろうか? この場合も等間隔ではなくなる点に注意して
P1P2^2=36h^2
P1P3^2=5m^2+25h^2
P1P4^2=8m^2+16h^2
P2P3^2=5m^2+h^2
P2P4^2=8m^2+4h^2
P3P4^2=5m^2+h^2
36h^2(1)=5m^2+h^2(2)<5m^2+25h^2(1)=
8m^2+4h^2(1)<8m^2+16h^2(1)
H6は
P3P4=P4P5=P5P6=√6
P3P5=P4P6=√10
P3P6=√12
であるから,
36h^2=5m^2+h^2=6,5m^2+25h^2=8m^2+4h^2=10
8m^2+16h^2=12
h^2=1/6,m^2=7/6はこれを満たす.
===================================
P1(0,0,0,0,0,0)
P2(0,0,0,0,0,6h)
P3(m√2,m√3,0,0,0,5h)
P4(m√8,0,0,0,0,4h)
Q(x,y,z,w,v)がH5を形成すればよいのであるが,
P2P3^2=5m^2
P2P4^2=8m^2
P3P4^2=5m^2
これが(5,5,8)なので(OK).
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