■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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