00:01
In this problem we're given a wave equation that is y of x t equals 3 .5 centimeters times the cosine of 2 .7 x minus 92 t.
00:22
We're also told that x here is in meters and t is in seconds.
00:32
And comparing this now to a normal wave equation, in general, traveling wave equation, let's say g for general.
00:42
We know that it's a, the amplitude.
00:46
Usually it's written as a sign, k, which is the wave vector, kx minus omega, which is the angular frequency times t.
00:58
Oh, sorry, n plus phase, just depending on how if there is a starting face on the wave.
01:14
And in this case, the phase is 90 degrees.
01:17
That's why we get a cosine.
01:20
So that's pi half.
01:22
And then we get a a cosine, kx minus omega -t...