# Finding the period of a sinusoid

 Homework Sci Advisor HW Helper Thanks P: 12,482 That's a good question - what have you tried? i.e. what happens if you try to turn your product of sinusoids into a single trig function? This is: ##A\sin k(x+vt)## where ##A=\sin\omega t## considered at point ##x=a## right? Presumably ##\omega \neq kv## in this case? In which case, you have an equation of form: $$y(t)=\sin(\omega_1 t + \phi)\sin(\omega_0 t)$$
 Homework Sci Advisor HW Helper Thanks P: 12,482 The value of a just affects the relative phase between the two sinusoids. What I suggested with the breakdown was that you treat the sin(wt) as the amplitude of the sin(k(x+vt)) travelling wave. What is happening? Since you are only looking at the oscillations at one point in space, you are just multiplying sine waves together like you've shown: sin(δt)*sin(ωt) $$y(t)=\sin\delta t \sin\omega t$$ ... basically. What sort of shape is that wave? Do you know about beats? Do you know about amplitude modulation?
 P: 145 I don't know much about AM, but I do know that $$y(t)=\sin\delta t \sin\omega t$$ is a form of AM