Derivation of group velocity.

  • Thread starter chingel
  • Start date
  • #1
300
22

Main Question or Discussion Point

I was reading the derivation on Wikipedia:

http://en.wikipedia.org/wiki/Group_velocity#Derivation

Why is the first part before the integral sign ignored when calculating the velocity? Surely it would also cause a phase shift in some time interval and make the waves move forward (or backward)?
 

Answers and Replies

  • #2
34,060
9,935
Group velocity cares about the speed of the amplitude, phases are not relevant for the group velocity.
 
  • #3
300
22
Ok, but when calculating the velocity by dividing the terms in front of t by those in front of k, why can some of the terms in front of t be ignored?
 

Related Threads on Derivation of group velocity.

Replies
3
Views
2K
Replies
3
Views
18K
Replies
10
Views
10K
Replies
3
Views
6K
Replies
3
Views
1K
  • Last Post
Replies
3
Views
1K
Replies
2
Views
3K
Replies
1
Views
4K
Top