MATLAB: Unable to compute series expansion

seriessymbolic integration

I have been trying to obtain a symbolic integration of a function. But unfortunately it seems I am unable to obtain a proper solution to the integral. So I tried expanding it as a series, but I am getting the following error. I have tried setting analytical constraints and also ignoring special cases during integration, but to no avail.
% Error
Unable to compute series expansion
% Code
syms x y z myu
R = 250e-06;
X = x/R;
Y = y/R;
Z = z/R;
v = 3.5e-03;
alpha = 5.375e-06;
sigma = R/alpha*v;
fun = exp((-((sigma)/(2*myu^2)+X)^2-Y^2)/(2*(myu^2+1))-Z^2/(2*myu^2))/(sqrt(2)*pi^(3/2)*(myu^2+1));
f = int(series(fun,myu,'ExpansionPoint',0,'Order',10),myu,0,Inf);
Kindly help me to resolve this problem of evaluating the symbolic integral. Thanks in advance.

Best Answer

The function includes z squared divided by 2 times myu squared. The first term of the series requires evaluation at the expansion point, which involves z squared divided by twice 0 squared which is either nan or infinite.
You cannot just skip the first term either: because of the chain rule you introduce more division by myu in the derivatives and those give problems evaluated at 0.
You would need to expand around a different point.