I found a notebook that symbolically applies the multiple time scales method to any differential equations. I don't like just using other people's code so I am going through the author's work line by line. I am new to Mathematica so I am looking up each function and reading about the syntax as I go through the code. Unfortunately I am running into issues because it appears the Mathematica language has changed since the creation of the notebook.
I think I was able to fix the first error I received by removing the <<Algebra ReIm;
line since it seems ReIm is an outdated package. The second error I am receiving is
Function::flpar: "Parameter specification {T[0],T[1]} in Function[{T[0],T[1]},Cos[ω\ T[0]]\ C[1][T[1]]+Sin[ω\ T[0]]\ C[2][T[1]]] should be a symbol or a list of symbols."
Which I get from line
zerosol = DSolve[zeroordereqn == 0,
x[0], {T[0], T[1]}] /. {C[_][#2]*Cos[omega_.*#1] + C[_][#2]*Sin[omega_.*#1] ->
A[#2]*Exp[I*omega*#1] + Conjugate[A[#2]]*Exp[-I*omega*#1]}
I am not sure how to fix this error, I believe it has to do with T[ 0 ] and T[ 1 ] not being initialize properly. I would appreciate any help with the issue.
I have included a link to the notebook file in case you need more information to help answer this question.
I am sorry if this is a simple question, but I am pretty new to Mathematica and not sure where to look to find the solution.
Thanks in advance,
Casey