# Nonrelativistic limit

1. Sep 19, 2007

### ehrenfest

1. The problem statement, all variables and given/known data
For problem 6.2, in the expression x = a sigma/ sigma_1, sigma is the spatial parameter but what is sigma_1 and is a the x-coordinate of one endpoint of the string?

Also, can someone give the first step I should take in order to solve this problem?

2. Relevant equations

3. The attempt at a solution

Last edited: Sep 19, 2007
2. Sep 21, 2007

### ehrenfest

does my question make sense to people?

3. Sep 21, 2007

### nrqed

zwiebach uses the somewhat confusing notation that for an open string, sigma ranges from 0 to $\sigma_1$ so $\sigma_1$ is indeed the coordinate corresponding to the extremity of the string. Therefore x ranges from 0 to a (so a is the length of the string).