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Homework Help: Asking for hint to MTW's problem

  1. Jan 11, 2012 #1
    1. The problem statement, all variables and given/known data

    Page. 124, MTW Gravitation. Exercise 4.6.

    Verify that the expressions given for the electromagnetic field of an oscillating dipole in equations (4.23) and (4.24) satisfy [itex]dF=0[/itex] everywhere and [itex]d*F=0[/itex] everywhere except at the origin.

    2. Relevant equations

    (4.23) [itex]F=[/itex]real part of [itex]\left\{p_1e^{iω(r-t)}[2\cos θ(1/r^3-iω/r^2)dr\wedge dt+\sin θ(1/r^3-iω/r^2-ω^2/r)rdθ\wedge dt+\sin θ(-iω/r^2-ω^2/r)dr \wedge rdθ]\right\}[/itex]

    (4.24) [itex]*F=[/itex]real part of [itex]\left\{p_1e^{i(r-t)}[\sin \theta(-i\omega /r^2-\omega^2/r)dt \wedge r\sin\theta d\phi+2\cos\theta (1/r^3-i\omega /r^2)rd\theta \wedge r\sin\theta d\phi+\sin\theta (1/r^3-i\omega /r^2-\omega^2/r)r\sin\theta d\phi\wedge dr]\right\}[/itex]

    3. The attempt at a solution

    It is easy to show that [itex]dF=0[/itex] and [itex]d*F=0[/itex] everywhere except at the origin. But how to show [itex]dF=0[/itex] at the origin, while [itex]d*F≠0[/itex] at the origin?
  2. jcsd
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