Complex logarithm - Wikipedia
In complex analysis, a complex logarithm of the non-zero complex number z, denoted by w = log z, is defined to be any complex number w for which e w = z. This construction is analogous to the real logarithm function ln, which is the inverse of the real exponential function e y, satisfying e lnx = x for positive real numbers x.. Since any complex number has infinitely many complex logarithms ...