arctanh

[hp-zl]

Because it's the same.
This follows from the definition of logarithm for complex numbers.
The complex part is k*fi, where k is any integer.
Enter e.g. tanh( ln(3)/2 - i*pi/2*5) and press Shift-Enter - you will get 2.

Regards.

PS.
Ln(r *exp(i*fi) = ln r + i*(fi + 2*k*pi)