Variation of parameters. unsure why my solution differs from professor's

fufufu
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Homework Statement


what is general solution of 2y'' - 3y' + y = ((t^2) + 1)e^t

Homework Equations



my particular solution is: (e^t) ((2/3)(t^3) + 6t -4))
prof particular solution is: ((1/3)(t^3)(e^t)) - 2(t^3)(e^t) + 9(te^t)

The Attempt at a Solution


here is how i solved , i hope this is ok to post link tp pdf..its faster than typing this all out..
https://docs.google.com/open?id=0BwJqUg33PgREQTFaejBCUkRRWlNfRW9maU1oaDNYQQ

thanks for any help/advice/hints
 
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You can check if your solution is correct by substituting back into the original equation. ehild
 
As the coefficient of y'' is not 1 in the original equation, you have to divide the right-hand side by 2 when calculating u' and v'.

I think you did not copy your professor's solution correctly. It has to be
(1/3 t3-2t2+9t)et.

ehild
 
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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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