# Toronto Math Forum

## MAT334--2020S => MAT334--Lectures & Home Assignments => Chapter 2 => Topic started by: serena li on March 01, 2020, 10:18:13 PM

Title: 2.4
Post by: serena li on March 01, 2020, 10:18:13 PM
For the question asking to find the power-series expansion about the given point for the function and find the largest disc where the series are valid, I am confused about how to find the valid largest disc. Thank you so much.
Title: Re: 2.4
Post by: Victor Ivrii on March 07, 2020, 08:08:06 AM
Either investigate the power series or to use theorem that if $f$ is analytic in some disc $D(z_0,r)$, then the expansion at its center $z_0$ converges in this disc.