1. Feb 10, 2008

### babblingsia

Suppose I have a FINITE wave train, ( of an unspecified nature), and it propagates along say the positive x axis with a constant speed v and without any change of shape. Now which differential equation it MUST satisfy? The normal wave equation or the Schrodinger's equation?

2. Feb 10, 2008

### pam

The normal wave train. The shape of f(x-vt) is unchanged in the wave equation.
Since the Schrodinger equation involves d^2/dx^2 and d/dt, the shape will change.

3. Feb 10, 2008

### lightarrow

You have the same derivates in the normal wave equation.

4. Feb 10, 2008

### pam

The normal wave equation has d^2/dt^2.

5. Feb 11, 2008

### lightarrow

Yes, it's true.

6. Feb 12, 2008

### babblingsia

Ok so what if i havent specified that the shape changes or not? I thought the schrodinger's eqn was like the universal wave equation of sorts!

7. Feb 13, 2008

### pam

Because the Schrodinger equation is first order in time, it is more like the dispersion equation
(but with i d/dt) than the wave equation.