From: Sinichiro Dezawa <dezawa@...>
Date: 1996-12-18T18:29:15+09:00
Subject: [ruby-list:1364] Re: Rational and Complex

》From: keiju@shljapan.co.jp (石塚圭樹)
》Subject: [ruby-list:1359] Re: Rational and Complex 
》Date: Wed, 18 Dec 96 15:28:18 JST

> ところで, 冪乗根は, 
> 
> def invpow(n, d)
>   x = d
>   loop do
>     a = ((n - 1) * x**(n-1) + d/x)/n
>     return x if a >= x
>     x = a
>   end
> end

  a = (( d + ( n - 1 )*x**n )/( n * x**(n-1))

かな、、、