Week 2-C Power Series

Friday, May 17, 2013

2:13 PM

 Formal Power Series

A formal power series is a power series where we don't care about convergence.



Notation



• 
• 

 

Formal power series can be added and multiplied in the obvious way.



 

Equivalently,



 



 

Equivalently,



 

Example

Let





• Fn = Fibonacci number

 



 









 







 

 

Example







 



For



 

Multiplicative inverse



 

Example



 





 

Note







 

Note







 

Note







 



 





 

 

Example





 

We want





 







 







 









 

These are the Fibonacci numbers