Question

Calculus: determine the power series expansion for 1/(x^4 + 4) and its radius of convergence?

Answer 1

Well you could use something similar to the geometric series form:
\[\sum_{n=0}^{\infty}ar^n=1/(1-r) \iff |r|<1. \]
You can rewrite this as such I believe.

Answer 2

That should read =a/(1-r) sorry about that.

Answer 3

right right. i get ya. rearranging it to be something like \[1/4(1-(-1/4x^4))\]? where the radius of convergence would be \[\left| -1/4x^4 \right| < 1\]
there for \[\left| x \right|<\sqrt{2}\]

Answer 4

Thats what I got :D

Answer 5

Sweet thanks :)