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en/3.7.13.md
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| + | ### Statement | ||
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| + | $3.7.13.$ [Insert the problem statement] | ||
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| + | ### Solution | ||
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| + | Let $A$ and $B$ be previous and current positions of the source and $C$ be a point on the wavefront. Then, $AC/AB=c/v$, so the envelope of emitted spherical waves is the surface of a cone. The angle between the wavefront and the direction of the source is $\alpha=\arcsin(c/v)$. | ||
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| + | #### Answer | ||
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| + | [Insert a concise answer or boxed result] | ||
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| ### Statement | |||
| $3.7.13.$ [Insert the problem statement] | |||
| ### Solution | |||
|  | |||
| Let $A$ and $B$ be previous and current positions of the source and $C$ be a point on the wavefront. Then, $AC/AB=c/v$, so the envelope of emitted spherical waves is the surface of a cone. The angle between the wavefront and the direction of the source is $\alpha=\arcsin(c/v)$. | |||
| #### Answer | |||
| [Insert a concise answer or boxed result] | |||