Re: How to get the real and imaginary parts of a power series?

*To*: mathgroup at smc.vnet.net*Subject*: [mg80016] Re: How to get the real and imaginary parts of a power series?*From*: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>*Date*: Fri, 10 Aug 2007 06:42:35 -0400 (EDT)*Organization*: Uni Leipzig*References*: <f9gvbc$b90$1@smc.vnet.net>*Reply-to*: kuska at informatik.uni-leipzig.de

Hi, try ComplexExpand[Re[s] // Normal] Regards Jens Gordon Smith wrote: > Suppose s = Series[Cosh[(x + I y)u, {u,0,2}]. How can I get the real part 1 + 1/2(x^2 - y^2) u^2 + O(u^3) and the imaginary part x y u^2 + O(u^3) ? I thought ComplexExpand[Re[s]] should give me the real part of s, but it just gives me s unchanged. (Mathematica newbie here!) >