Summing a series on an interval of convergence

[c.dube]

Homework Statement

Find the interval of convergence of the series and, within this interval, the sum of the series as a function of x.
\sum^{\infty}_{n=0}\frac{(x-1)^{2n}}{4^n}

Homework Equations

N/A

The Attempt at a Solution

Finding the interval is easy, using the ratio test it reduces down to
|\frac{(x-1)^{2}}{4}|<1
-1<x<3

However, I have no idea how to do the second part. Any help?

 

[System]

1- You should check the end points to decide the interval.
2- For the sum, I think you know something called "geomtric series", right?

 

[c.dube]

Duh! Thanks.