推 hsnulight:這題我記得最近板上有你可以爬文一下 12/15 14:03
推 profyang:就你在某方向的k向量是虛數的話 證往該方向傳遞的能量是0 12/15 20:50
The mathematical expression for plane waves was well-known to you. Please
verify the net energy transmission (or flow) of the above-mentioned plane wave
is zero along the direction where the component of its propagation vector is
pure imaginary.
有點不能了解題意，所以不知道該如何下筆
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