Question

I don’t know how to solve for this. Could you please show me the steps involved. I am unable to combine equation 1 and 2 to get equation 3. I would like to see the working out so I can learn from it.

Answer 1

They replaced phi with 2pi*vt, then factored out the common factor 2pi.

`y = A\sin\left(\phi - (2\pi)/(\lambda)x\right)\\\\y = A\sin\left(2\pi vt - (2\pi)/(\lambda)x\right)\\\\y = A\sin\left(2\pi vt - 2\pi(x)/(\lambda)\right)\\\\y = A\sin\left(2\pi\left(vt - (x)/(\lambda)\right)\right)\\\\`

Hopefully that clears things up. If not, then let me know.