- #1

brianhawaiian

- 12

- 0

## Homework Statement

"Find the radius of convergence of the power series for the following functions, expanded about the indicated point.

1 / (z - 1), about z = i.

## Homework Equations

1 / (1 - z) = 1 + z + z^2 + z^3 + z^4 + ... +

Ratio Test: limsup sqrt(an)^k)^1/k

## The Attempt at a Solution

1 / (z - 1) = -1 / (1 - z) = -1(1 + z + z^2 + z^3 + z^4 + ... +)

Ratio test gives 1?

Answer but I'm not sure how sqrt(2)