# Homework Help: How to Find Multiple Phase Constants

1. Jun 6, 2015

### rockerdude1210

1. The problem statement, all variables and given/known data
A sinusoidal wave traveling in the –x direction (to the left) has an amplitude of 20.0 cm, a wavelength of 35.0 cm and a frequency of 12.0 Hz. The transverse position of an element of the medium at t = 0, x = 0 is y = –3.00 cm and the element has a positive velocity here. (a) Sketch the wave at t = 0. (b) Find the angular wave number, period, angular frequency and wave speed of the wave. (c) Write an expression for the wave function y(x,t).

2. Relevant equations

y=Asin(kX-wt)

3. The attempt at a solution

I solved for the phase constant by subbing in the initial values and found -0.151 rad. however, the solution said that there are other possible phase constants, such as π + 0.151 rad and 2π - 0.151rad, etc. I was wondering if someone could explain how to find the other phase constant values.

Thanks

2. Jun 6, 2015

### Simon Bridge

Hint: the sine wave is periodic.

3. Jun 7, 2015

### rockerdude1210

Oh okay,

so would you just add or subtract 180 degrees to whatever phase constant you found?

4. Jun 8, 2015

### Simon Bridge

A sine wave has the same overall phase if both the value and the slope are the same.
Use the periodicity of the sine wave you have, if you are uncertain then sketch out the first few periods and see - and put all angles in radians.

5. Jun 9, 2015

Thanks!