Series Expansions in Mathematica

*To*: mathgroup at smc.vnet.net*Subject*: [mg129871] Series Expansions in Mathematica*From*: Samuel Mark Young <sy81 at sussex.ac.uk>*Date*: Tue, 19 Feb 2013 18:53:54 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*Delivered-to*: l-mathgroup@wolfram.com*Delivered-to*: mathgroup-newout@smc.vnet.net*Delivered-to*: mathgroup-newsend@smc.vnet.net

Hello, I am attempting to expand an equation, and then solve the 1st, 2nd, 3rd, 4th and 5th order expressions one at a time. The equation is: Exp[4 x] - c Exp[3 y] Exp[4 x] + c - 1 = 0 With, x and y small variables to be expanded and c a constant. Once this is expanded, the variables x and y are in turn replaced with expansions written as: x = x[1] + x[2]/2 + x[3]/6 + x[4]/24 + x[5]/120 (to 5th order) By the time I have completed these expansions, I have a somewhat long expression. Does Mathematica have an intelligent way of deciding which terms would be 1st/2nd/etc order? For example, x[1] y[2] and x[1]^2 y[1] would both be third order. Many thanks, Sam Young

**Follow-Ups**:**Re: Series Expansions in Mathematica***From:*Bob Hanlon <hanlonr357@gmail.com>