■葉序らせん(その35)

 s^2=3/5,c^2=2/5,y=√3/5

  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)

AO^2=BO^2=y^2+s^2/4

CO^2=(y−√3/2)^2

DO^2=EO^2=(y−√3/6)^2+2c^2/3

FO^2=(y−β)^2+(αc−γs)^2

GO^2:(y−η)^2+(ξc−ηs)^2

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cos(∠AOC)=(−9/50)/(1/4+3/25)^1/2・3√3/10=(−9/50)/√37/10・3√3/10=−6/√37√3

cos(∠AOE)=(sc√(2/3)+1/50)/(1/4+3/25)^1/2・(2/3+1/30)^1/2=(√6/5√(2/3)+1/50)/√37/10・√(7/10)=21/50/√37√7/10√7

cos(∠COE)=(−9/100)/3√3/10・(2/3+1/30)^1/2=(−9/100)/3√3/10・√(7/10)

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