Probably if x^n =Am ((a/b)π), x=e^(((2k+a)/(bn))iπ)
about 0<(k∈N∪{0})<(n∈N) and b≠0.
p.s. Am (0°)=1, Am (90°)=i etc.,
and s°=(π/(180))s rad(ians)=(π/(180))s.
Prove that to each quadratic factor in the denominator of the form
ax^2 + bx + c which does not have linear factors, there corresponds to
a partial fraction of the form ((Ax + B)/(ax^2 + bx + c)) where A and B are constant.