Velocity of Wave Packets

  1. Wave packets has a group velocity of

    [tex]v_{group}=\frac{d\omega}{dk}[/tex]

    and its phase velocity is

    [tex]v_{phase}=\frac{\omega}{k}[/tex]

    Show that the group velocity and the phase velocity are related by:

    [tex]v_{group} = v_{phase} - \lambda\frac{dv_{phase}}{d\lambda}[/tex]

    Can someone please tell me where to start on this problem?
     
  2. jcsd
  3. dextercioby

    dextercioby 12,294
    Science Advisor
    Homework Helper

    All u need to know besides the rules of differentiation is
    [tex] k=:\frac{2\pi}{\lambda} [/tex]

    Daniel.

    PS.Compute the RHS of your equality and show it matches the LHS.
     
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