# Homework Help: Help with understanding wave function

1. Aug 27, 2010

### jwxie

1. The problem statement, all variables and given/known data

Here are the screenshots of the textbook...

Code (Text):
http://i37.tinypic.com/nce7md.jpg
http://i36.tinypic.com/8zpwew.jpg
What I don't understand is the parameter (x - vt)

I am confused by the picture. This is why I can't even ask a precise question, and rather I can only ask a very general question, and I must apologize...

Question: Can someone explain to me what the picture shows, and how do I see (x - vt)? I see vt = d from mechanics. But the pictures are very confusing...

Sorry. and thank you!

2. Aug 28, 2010

### ehild

You certainly learnt in Maths how to shift a function. For example, when you have a parabola y=x^2, its minimum is at x=0. What is the equation of the parabola which has the same shape, only the minimum is shifted along the x axis to x=d?

ehild

3. Aug 28, 2010

### jwxie

Hi ehild, Thanks!
It makes sense now, A horizontal shift would be a(x-h)+k where h is the horizontal shift. For the reverse direction (left), we would have -(-h) which agrees with the book.

Thank you!