# [Mathematica] Sorting polynomial terms

1. Dec 4, 2011

### jackmell

Hi. Can someone explain to me how to sort a Series so that the terms are in increasing powers of the exponent? For example the code:

myseries = Normal[ Series[Sqrt[1 - w], {w, 0, 5}]] /. w -> 1/z

produces
$$1-\frac{7}{256 z^5}-\frac{5}{128 z^4}-\frac{1}{16 z^3}-\frac{1}{8 z^2}-\frac{1}{2 z}$$

I would like them to be

$$1-\frac{1}{2z}-\frac{1}{8z^2}-\cdots$$

Thanks,
Jack

2. Dec 4, 2011

### Hurkyl

Staff Emeritus
You can make a series around $\infty$. I don't know if that will appear sorted the way you want.

3. Dec 4, 2011

### jackmell

Sorry. I'm afraid I'm having some problems with this. The series is being reported by Mathematica in increasing powers of 1/z like it should and like I'd want it to be.

Thanks Hurky for suggesting expanding it around infinity which is what I'd want for the function outside the unit circle.

Last edited: Dec 4, 2011
4. Dec 4, 2011

### Bill Simpson

myseries = Normal[Series[Sqrt[1 - w], {w, 0, 5}]] /. w -> 1/z;

5. Dec 4, 2011

### Hepth

Series[Sqrt[1 - w] /. w -> 1/z, {z, \[Infinity], 5}]

6. Dec 5, 2011

### jackmell

Ok, thanks guys. TraditionalForm does what I wanted.