Finding a Second Linear Solution using Reduction of Order Method for ODEs

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Homework Statement



Use the method of reduction of order to find another independently linear solution y2(x) when given one solution.

x^2y'' - x(x+2)y' + (x+2)y = 0

y_1(x) = x

The Attempt at a Solution



Hopefully y2(x) will take the form of v(x)y1(x) or I have no idea how to solve the ODE. I start by finding y'2(x) and y''2(x).

y_2 = vx
y'_2= v + xv'
y''_2 = v' + v' + xv'' = 2v' + xv''

I substitute the above into the equation:

x^2(2v' + xv'') - x(x+2)(v + xv') + (x+2)vx = 0

2x^2v' + x^3v'' - x^2v - x^3v' - 2xv - 2x^2v' + x^2v + 2xv = 0

And this is where I've gotten to. Everything cancels out and I can't see how I'll find my v...
 
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You have two terms left over: ##x^3 (v'' - v')=0##.
 
Oh, wow. I overlooked the same thing three times...

Might be worth switching notation to avoid this from happening again.

Thanks.
 
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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