Interpreting this wave funtion

1. Oct 23, 2008

RJS

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

find Amplitude, wavelength and velocity of wave from the two combined waves.

there are two waves here, combined into one, show each wave function: y1(x,t) and y2(x,t).

2. Relevant equations

ok, i can fully manipulate the wave function when it's in it's basic form of y(x,t)=Acos(kx-wt+phi) but i must be missing something here. is the problem in a form that can be worked or must it be reworked with a trig function? it's all being multiplied so i'm not sure how to get it into the (kx-wt) format.

any help would be appreciated.

thanks.

3. The attempt at a solution

because they are two waves in this equation Amplitude is (4.8mm/2)=2.4mm... correct?

wave length can be found using kx= [2(pi)x]/(lambda) and velocity will be found using wt=2(pi)tf to find frequency and then v=(lambda)(frequency)

my question is do i need to change the equation? or can i just use it as is?

I don't have the answer to this question, so if you can point me in the right direction?

Last edited: Oct 23, 2008
2. Oct 23, 2008

Redbelly98

Staff Emeritus
You're correct on amplitude, wavelength, frequency and velocity.

In addition, yes you will need to change the equation, since it asks explicitly to "show each wave function: y1(x,t) and y2(x,t)."

If you can figure out how to express
sin(a)cos(b)
in terms of
sin(a+b), sin(a-b), cos(a+b), and/or cos(a-b)
using trig-addition identities, then it is solvable.