■葉序らせん(その25)

 y軸の回りに回転させると

  A(-s/2,0,c/2)

  C(0,√3/2,0)

  D(c√(2/3),√3/6,s√(2/3))

  E(-c√(2/3),√3/6,s√(2/3))

  F(αc-γs,β,αs+γc)

  G(ξc-ζs,η,ξs+ζc)

  O(0,y,0)

 DE,CGは

 (y-√3/6)^2+2c^2/3

=(y-√3/2)^2

=(y-η)^2+(ξc-ηs)^2

y^2-y√3/3+1/12+2c^2/3

=y^2-y√3+3/4

=y^2-2ηy+η^2+ξ^2c^2-2ξηcs+η^2s^2

√3y-1+c^2=0

(2η-√3)y+3/4-η^2-ξ^2c^2+2ξηcs-η^2s^2

√3y=s^2

このあとが続かない.

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 A,C,Fは

  y^2+s^2/4=(y-√3/2)^2=(y-β)^2+(αc-γs)^2

=y^2-√3y+3/4

=y^2-2βy+β^2+(αc-γs)^2

4√3y+s^2-3=0

このあとが続かない.

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4√3y=4s^2

4√3y=3-s^2

s^2=3/5,c^2=2/5,y=√3/5

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