■葉序らせん(その40)
(その33)を訂正.
A(−s/2,−√3/5,c/2)
B(s/2,−√3/5,c/2)
C(0,3√3/10,0)
D(c√(2/3),−√3/30,s√(2/3))
E(−c√(2/3),−√3/30,s√(2/3))
F(αc−γs,β−y,αs+γc)
G(ξc−ζs,η−y,ξs+ζc)
O(0,0,0)
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cos(∠AOB)=(−s2/4+3/25)/(s^2/4+3/25)
s^2=3/5,c^2=2/5を代入すると
cos(∠AOB)=(−3/20+3/25)/(3/20+3/25)
=−3/27=−1/9
cos(∠DOE)=(−2c^2/3+1/300)/(2c^2/3+1/300)
=(−4/15+1/300)/(4/15+1/300)
=−79/81
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