Griffiths Page 146: Understanding Binomial Expansion

[ehrenfest]

[SOLVED] Griffiths page 146

Homework Statement

EDIT: sorry I realized I posted this in the wrong forum; someone can move it to the advanced physics forum if you want

Please stop reading unless you have Griffiths E and M book.

On that page, Griffiths says "and then the binomial expansion yields" and I am not sure what binomial expansion he is talking about. On the next line how did he get the second approximate equality? How in the world did he get rid of the ( )^(-1/2) operation ?

Homework Equations

The Attempt at a Solution

 

[ehrenfest]

Never mind. See equation 3.93.