■代数学の基本定理とiの1/2乗とガロア理論(その42)
i=exp(iπ/2)・・・虚軸上の点
i^i=exp(i^2π/2)=exp(−π/2)・・・実軸上の点
i^i^i=exp(iπ/2)^exp(−π/2)
=exp(iπ/2exp(−π/2))
=cos{π/2exp(−π/2)}+isin{π/2exp(−π/2)}・・・単位円周上の点
i^i^i^i=・・・
i^i^i^i^i=・・・極限値はどのような1点に収束するのだろうか?
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i^ω=ω
この超越方程式は、
(-iπ/2・ω)exp(-iπ/2・ω)=-iπ/2
と書き直すことができて、ランベルトのW関数を用いて
i^i^i^i^i・・・=i2/π・W(-iπ/2)=0.4382829367+0.3605924719i
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i^i^i=exp(iπ/2)^exp(−π/2)=cos{π/2exp(−π/2)}+isin{π/2exp(−π/2)}・・・単位円周上の点
において、r=1,t=π/2exp(−π/2)とおく.
i^i^i^i=exp(iπ/2)^(rcost+irsint)=exp{-π/2rsint+iπ/2rcost}
=exp{-π/2rsint}{cos(cos(π/2rcost))+isin(cos(π/2rcost))}
R=exp{-π/2rsint},T=cos(π/2rcost)とおく。
i^i^i^i^i=exp(iπ/2)^(RcosT+iRsinT)=exp{-π/2RsinT+iπ/2RcosT}
=exp{-π/2RsinT}{cos(cos(π/2RcosT))+isin(cos(π/2RcosT))}
調和散歩のようには表すことができない。
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i=exp(iπ/2)=cos(π/2)+isin(π/2)
i^i=exp(iπ/2)^exp(iπ/2)
i^i=exp(iπ/2)^{cos(π/2)+isin(π/2)}
i^i=exp(iπ/2{cos(π/2)+isin(π/2)})
i^i=exp(-π/2sin(π/2)+iπ/2{cos(π/2)})
i^i=exp(-π/2sin(π/2)){cosπ/2{cos(π/2)}+isin(π/2{cos(π/2)})}
i^i=exp(−π/2)
i^i^i=exp(iπ/2)^exp(−π/2)=exp(iπ/2exp(−π/2))
=cos{π/2exp(−π/2)}+isin{π/2exp(−π/2)}
r=1,t=π/2exp(−π/2)とおく.
i^i^i^i=exp(iπ/2)^(rcost+irsint)=exp{-π/2rsint+iπ/2rcost}
=exp{-π/2rsint}{cos(cos(π/2rcost))+isin(cos(π/2rcost))}
R=exp{-π/2rsint},T=cos(π/2rcost)とおく。
i^i^i^i^i=exp(iπ/2)^(RcosT+iRsinT)=exp{-π/2RsinT+iπ/2RcosT}
=exp{-π/2RsinT}{cos(cos(π/2RcosT))+isin(cos(π/2RcosT))}
U=exp{-π/2Rsint},V=cos(π/2RcosT)とおく。
i^i^i^i^i^i=exp(iπ/2)^(UcosV+iUsinV)=exp{-π/2UsinV+iπ/2UcosV}
=exp{-π/2UsinV}{cos(cos(π/2UcosV))+isin(cos(π/2UcosV))}
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