Undetermined coefficient method

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Homework Statement


y''+10y'+25y=x+2+3e-5*x

Homework Equations

The Attempt at a Solution


F(D) = D2+10D+25 zeroes: -5
yc= C1*e-5*x + C2*e-5*x *x

yp = ax+b + C*e-5*x
yp = ax+b + C*e-5*x*x2

I just want to know if my yc and yp is correct, after that I know how to do it.
 
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yc is correct, yp is not. The SECOND yp, ax+ b+ cx^2e^{-5x} is correct. Since e^{-5x} and xe^{-5x} satisfy the associated homogenous equation you need the "x^2".
 
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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