sqrt(z) -> Float | Complex
z の平方根を返します。
例 require "cmath" CMath.sqrt(-1) # => (0+1.0i) CMath.sqrt(1)# => 1.0 CMath.sqrt(Complex(0, 8))# => (2.0+2.0i)
require "cmath" CMath.sqrt(-1) # => (0+1.0i) CMath.sqrt(1)# => 1.0 CMath.sqrt(Complex(0, 8))# => (2.0+2.0i)