# Homework Help: Two Transverse Sinusoidal waves combine in a medium

1. Jul 1, 2013

### Willjeezy

1. The problem statement, all variables and given/known data
Two Transverse Sinusoidal waves combine in a medium are described by the wave functions:

y1 = 3sin∏(x + 0.600t)

y2 = 3sin∏(x - 0.600t)

what is y1 + y2?

2. Relevant equations
the hint is that I am supposed to use:
sin(α + β) = sin(α)cos(β) + cos(α)sin(β)

3. The attempt at a solution
the answer in the back is:
y = y1 + y2 = 6sin(∏x)cos(0.600∏t)

I am not really sure how they got that. In fact,the notation of y1 and y2 confuse me because y1 says:

y1=3sin∏(x + 0.600t)

and I interpret this as 3 multiplied by sin∏ multiplied by (x+0.600t)

but the problem is sin∏ = 0, so don't both equations just reduce to 0?

y1 = 0
y2 = 0?

Can someone clarify this for me?

2. Jul 1, 2013

### rude man

No. 3sin[π(x + 0.6t)] means "three times the sine of the angle π(x + 0.6t)".

3. Jul 1, 2013

### Willjeezy

hmm.

3sin[π(x + 0.6t)]

it was written verbatim as:
3sin∏(x + 0.600t)

thanks, rude man.

Last edited: Jul 1, 2013
4. Jul 1, 2013