Write a 2nd order DE given two particular solutions

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PNGeng
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The question is:

Find a second order linear equation which has y1=-3e^(2t) and y2=e^(2t)+2te^(2t) as two of its particular solutions.

Attempt at a solution:

Since it's a repeated root problem, we know r=2, therefore the characteristic equation must look like (r-2)^2=0

r^2-4r+4=0 ----------------------- > y''-4y'+4y=0
Is this problem really that easy? I have a feeling I'm misinterpreting the question cause this is way too trivial.
 
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Yes, it is that easy. Enjoy it. :smile:
 
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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