Eliminating First Derivative in Tricky Differential Equation | Homework Help

outhsakotad
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Homework Statement


xy''+2y'+(n^2)*x*y=sin(omega*x)

Hint: Eliminate the first derivative term


Homework Equations





The Attempt at a Solution



I have tried lots of substitutions, but none of them seems to work out. I don't really understand what the hint is getting at. For example, I've tried y'=ux, but then I don't know what to do with the y. I've tried y=ux, but that doesn't seem to help matters at all. And I've tried numerous other silly things that haven't worked out. I'm really out of ideas and stuck. Any little hints would be greatly appreciated.
 
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You notice that xy'' + y' looks very much like the derivative of a product.

So I suggest you try playing around with u = xy' or x(y'2); and if that doesn't work maybe u = xy
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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