■フルヴィッツ曲線(その23)

【1】フルヴィッツ曲線の回転

もっと簡単な形にできるかもしれない

逆回転では

-2sin((2n-2)β)-4cos(n-1)β=-4cos(n-1)β{sin(n-1)β+1}

2{sin(nβ)+sin(n-2)β+2cosβ}cos(nθ)={2sin(n-1)βcosβ+2cosβ}cos(nθ)

2{cos(nβ)-cos(n-2)β-2sinβ}sin(nθ)=={-2sin(n-1)βsinβ-2sinβ}sin(nθ)= 0

-2sin((2n-2)β)-4cos(n-1)β=-4cos(n-1)β{sin(n-1)β+1}

2{sin(nβ)+sin(n-2)β+2cosβ}cos(nθ)=4{sin(n-1)β+1}cosβcos(nθ)

2{cos(nβ)-cos(n-2)β-2sinβ}sin(nθ)==-4{sin(n-1)β+1}sinβsin(nθ)= 0

C=cos(n-1)β

B=cosβ

A=-sinβ

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順回転では

2sin((2n-2)β)+4cos(n-1)β

2{sin(nβ)+sin(n-2)β+2cosβ}cos(n-2)θ)

2{cos(nβ)-cos(n-2)β-2sinβ}sin(n-2)θ)=0

C=-cos(n-1)β

B=cosβ

A=-sinβ

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Asin(mθ)+Bcos(mθ)=C

の形に整理されました.

 A,B,Cの具体的な形は割愛し考え方を示すにとどめますがますが,ここで

  cosψ=A/(A^2+B^2)^(1/2),

  sinψ=B/(A^2+B^2)^(1/2),

  tanψ=B/A

とおくと,

  sin(mθ+ψ)=C/(A^2+B^2)^(1/2)

より

  mθ=−arctan(B/A)+arcsin(C/(A^2+B^2)^(1/2))

 =−arctan(B/A)+arctan(C/(A^2+B^2−C^2)^(1/2))

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