# Wave function

1. Apr 21, 2007

### Helicobacter

In my text
y(x,t)=Acos(kx-ω t)
In the teacher's handout:
y(x,t)=Asin(kx-ω t)
There's a translational difference of pi/2 between them! I don't know which one to use for the test :S

2. Apr 22, 2007

### zergju

hehe, its just a matter of initial condition (with difference of pi)
and thereotically an ideal sound wave is usually calculated for a stablized value which means the initial condition doesnt matter much.. very seldom do we need to know its initial condition..
so no matter sin or cos will end up with e same results.
and u can use either one u want due to different kinds of calculations

3. Apr 22, 2007

### AlephZero

To be accurate, there's a translational difference of pi/2k between them.

Or looking at it a different way, there is a time difference ot pi/2ω

As zergju says, they both represent "the same wave motion", but measured relative to differet points in space and/or time.

4. Apr 22, 2007

### Helicobacter

That was helpful, thanks

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