Am I crazy or is my book wrong?

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yjl
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Hey all,

My book says/does the following.

Use the following equation for a plane wave
Equation: Φ(t, x, y, z) = Φ₀ e^(i k_z x + i k_y y + i k_z z − iωt), a plane wave expression with amplitude Φ₀ and phase depending on t, x, y and z.

Fill it in the klein-gordon equation
Klein-Gordon equation written as (1/c^2) d^2 phi/dt^2 - del^2 phi + mu^2 phi = 0.

To get
Equation: [(ω/c)^2 - k_x^2 - k_y^2 - k_z^2] φ(t, x, y, z) = 0, a Klein-Gordon-type wave equation written with ω/c and wavevector components.

Which results in
Equation written as omega squared equals the absolute value of k squared times c squared plus mu squared times c to the fourth power.


Is this right? I got something different and no matter how hard I try I can't replicate the same answer. I've gotten the last equation, but without the c to the power of 4. I also feel like they just flat out forgot μ in the third equation.
 
yjl said:
I've gotten the last equation, but without the c to the power of 4.
It should be ##\omega^2 = c^2 k^2 + c^2 \mu^2##, where ##k^2 = k_x^2 + k_y^2 + k_z^2##; if this is what you got then you did it correctly
yjl said:
I also feel like they just flat out forgot μ in the third equation.
Yes.

By the way, what book is this?

Jason
 
jasonRF said:
It should be ##\omega^2 = c^2 k^2 + c^2 \mu^2##, where ##k^2 = k_x^2 + k_y^2 + k_z^2##; if this is what you got then you did it correctly

Yes.

By the way, what book is this?

Jason
Yes, thank you!

That's what I kept ending up on. :-)

It's not a book that's publicly available. It's my professor's LaTeX book that he wrote for the course. He did say that it's still very much a work in progress, but still..
 
yjl said:
It's my professor's LaTeX book that he wrote for the course
I hope you'll tell him about this, politely. If it were me, I would appreciate the feedback. :oldwink:
 
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jtbell said:
I hope you'll tell him about this, politely. If it were me, I would appreciate the feedback. :oldwink:
Yes, I e-mailed him. Wonder if he'll appreciate or find it annoying to be honest
 
yjl said:
Yes, I e-mailed him. Wonder if he'll appreciate or find it annoying to be honest

If he finds it annoying that someone pointed out a mistake in his text, then he has no business being a physicist, or an educator for that matter.

Zz.
 
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