# Optics: Determine which of the following describe traveling waves

1. Oct 9, 2011

### Shackleford

I'm really rusty on waves. What characteristics am I looking for? With respect to its variables, doesn't a valid wave equation have to contain only linear terms in its argument(s)?

http://i111.photobucket.com/albums/n149/camarolt4z28/IMG_20111009_211512.jpg?t= [Broken]

Last edited by a moderator: May 5, 2017
2. Oct 9, 2011

### ehild

Yes, a wave has the form f(ax-bt).

ehild

3. Oct 13, 2011

### Shackleford

Yes, I know that.

It appears (d) is valid, but what about (a), (b), and (c)? I guess I'm not sure what the squares do. Of course, I recognize the form of the equation without the squares.

Last edited: Oct 13, 2011
4. Oct 13, 2011

### SammyS

Staff Emeritus
Having (ax±bt)2 shouldn't matter. The squaring can be considered to be part of function, f .

5. Oct 13, 2011

### Shackleford

Same goes for cos2, too?

6. Oct 13, 2011

### SammyS

Staff Emeritus
Yes.

7. Oct 14, 2011

### Shackleford

What about (b)? It has az2 - bt2.

8. Oct 14, 2011

### ehild

If it is a travelling wave, in what direction does it travel? +z or -z?

ehild