Dear all, I am trying to use the associated Legendre polynomials, but I am confused about the sign. I would expect P_1^1(cos(phi)) = sin(phi) > 0 and therefore to have the normalised polynomial also positive. However, it seems that there is a (-1)^m multiplier compared to the expression I see in several books. Could someone please clarify this issue for me?
Kind regards, Denis
