Re: Problem with Series

*To*: mathgroup at smc.vnet.net*Subject*: [mg113955] Re: Problem with Series*From*: Themis Matsoukas <tmatsoukas at me.com>*Date*: Fri, 19 Nov 2010 05:09:18 -0500 (EST)

That's interesting but it creates more questions than it answers: 1. If I include the second term of the expansion, this method does not work any more: f = Log[Coth[1/2 ArcCosh[Sqrt[1 + x^2]/x]]]; Series[f, {x, 0, 2}] fLinearized = FullSimplify[Normal[%]] fLinearizedLinearized = Normal[Series[fLinearized, {x, 0, 2}]] Series produces what looks like a power series, but Normal returns a single non linear function, not a polynomial in x. 2. If I replace FullSimplify with Simplify in your original solution, the second series does not work. Incidentally, I was able to obtain the full power series by expressing the original function in different form. My question here is really about how Mathematica does things. Themis Themis