00:01
So in this question, we have the interface of two different waves that has a face difference.
00:09
So let's first write out the general form of these type of questions.
00:13
If we have one wave that is ym sine of kx minus omega -t, and then we have another wave that is completely the same except for a face difference plus five.
00:30
Then what we can do is that we can think of this is si x minus omega t plus 5 over 2 minus 5 over 2 and this is side k x minus omega t plus 5 over 2 why because then we can use the angle addition formula for the sign function so this one if we call call this alpha and we call this beta, and similar if we call this alpha and we call this beta, this is equal to sine alpha cosine beta minus cosine alpha, sine beta, plus this one we have sine alpha, sine beta, plus cosine alpha, sine beta.
01:32
So these two cancel and we're left with two times sine alpha, cosine, and in this case, cosine beta is 5 over 2.
01:44
Inside, alpha is kx minus omega -t plus 5 of 2.
01:47
So if you put back the number, we have 2 2 times 5 over 2, then sign x minus omega -t plus 5 over 2.
01:58
So this is what happens when we add up to senu -soidal equations with a phase difference.
02:04
In this case, we have a phase difference of pi over 2...