00:01
In this problem, we are talking about an introduction to the calculations that you would be doing in a boundary valued problem.
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And that's what we're going to be talking about today, how to go through that process in order to get a final solution.
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So let's first review what we're given.
00:19
We have that y double prime plus 4y equals the cosine of x.
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And we're also given some conditions about what y prime equals.
00:28
So let's first find the homogeneous part of our solution.
00:32
Well, we can see that r squared equals 4.
00:36
So if we were to find r by itself, we would get plus or minus 2i, if we just take the square root of each side.
00:43
So what does that tell us? that tells us that alpha equals 0 and beta equals 2.
00:49
So now we can plug these values in to an equation.
00:53
So we're going to end up with y equals c1 times the cosine of 2.
00:58
2x plus c2 times the sign of 2x.
01:02
So then we want to find these coefficients...