trilogarithm
Assuming "trilogarithm" is a math function | Use as or instead

Input

Li_3(z)

Branch point

z = 1

Series expansion at z=0

z + z^2/8 + z^3/27 + z^4/64 + z^5/125 + O(z^6)
(Taylor series)

Derivative

d/dz(Li_3(z)) = (Li_2(z))/z