I want to be able to extract from mathematica, an undertermined gauges, like in pertubation theory: $$\delta_0(\epsilon)x_0+\delta_1(\epsilon)x_1+\cdots+\delta_k(\epsilon)x_k $$ And to extract the guages (deltas) and the coefficients (x_i's) from the code, how do you propose me to code this? To clarify what I mean. In pertubation theory for solving polynomial roots, we have two methods either to expand in a power series of epsilons, and then plug back to the pertubed polynomial equation, or to use the method above of undetermined gauges. In the attachment there's example for power series, I want to use this to an equation where only undtermined gauges will work, so I neet to change the first root and second to find coefficients $x_1,x_2$ and the suitable gauges. Anyway here's the term undetermined gauges: http://books.google.co.il/books?id=...6AEwAw#v=onepage&q=undetermined gauge&f=false P.S you need to change after the .txt, to .nb, so that mathematica will read it.