I am trying to construct a series around infinity and I get the following result:
In[14]:= Normal@Series[ Sqrt[2 Pi x] BesselI[3, x]/Exp[x], {x, \[Infinity], 3}, Assumptions -> (x > 0)]
Out[15]=(-I + E^(2*x)*(1 + 945/(128*x^2) - 35/(8*x)) - (945*I)/(128*x^2) - (35*I)/(8*x))/E^(2*x)
Notice that x is assumed real which means that the result should not not have any imaginary terms but it does. What is going on here? And what is the best way to get rid of these terms?