# A Onde plane

1. Mar 12, 2016

### mathben

Pourquoi une onde plane n'a pas de réalité physique

2. Mar 12, 2016

### BvU

Hello Ben,

A plane wave such as $\cos x$ has no physical reality because it goes on to infinity in the y and z directions. It is, hoewever, a very good approximation in many situations, and easier to deal with than a representation of a more realistic wave.

3. Mar 13, 2016

### vanhees71

The most important feature of plane waves is that you can represent any real wave packet in terms of Fourier decompositions of plane waves (Fourier series and transforms).