Complex logarithm
(重定向自Imaginary logarithm)



In complex analysis, a complex logarithm function is an "inverse" of the complex exponential function, just as the real natural logarithm ln x is the inverse of the real exponential function e. Thus, a logarithm of a complex number z is a complex number w such that e = z. The notation for such a w is ln z or log z. Since every nonzero complex number z has infinitely many logarithms, care is required to give such notation an unambiguous meaning.