I am struggling with these question about branch cuts.

The function f(z) is given by:

f(z) = [(z-1)^p][(z+1)^q]

where p and q are real constants.

The branch of this function is chosen such that

0 <= arg(z +- 1) < 2 π

Show that, if and only if p + q = integer, a branch cut is not need on the section (1, ∞) of the real axis.

Deduce where the cut is in this case.