Variation of Parameters on a system of Differential Eqs (Simple question)

Saladsamurai
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Homework Statement


Okay so when solving a system of D.E.s using Variation of Parameters I know that first I find the complementary solution Xc and then do a bunch a of crap after that using the fundamental matrix.

Now I just came across a problem with repeated roots, so I just want to clarify that I am correct in saying that if the complementary solution looks like this:

X_c=c_1\left(\begin{array}{c}1\\1\end{array}\right)+c_2[\left(\begin{array}{c}1\\1\end{array}\right)t+\left(\begin{array}{c}1\\0\end{array}\right)]Then the fundamental matrix looks like this:

\Phi(t)=\left(\begin{array}{cc}1 & t+1\\ 1 & t\end{array}\right)
Just a yes or no will do... (if it's no, I am in trouble!)

Thanks!
 
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Anyone? I just want to make sure before I go using this...
 
Well I thought it was a simple question...
 
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eat the food!
 
Saladsamurai said:

Homework Statement


Okay so when solving a system of D.E.s using Variation of Parameters I know that first I find the complementary solution Xc and then do a bunch a of crap after that using the fundamental matrix.

Now I just came across a problem with repeated roots, so I just want to clarify that I am correct in saying that if the complementary solution looks like this:

X_c=c_1\left(\begin{array}{c}1\\1\end{array}\right)+c_2[\left(\begin{array}{c}1\\1\end{array}\right)t+\left(\begin{array}{c}1\\0\end{array}\right)]


Then the fundamental matrix looks like this:

\Phi(t)=\left(\begin{array}{cc}1 & t+1\\ 1 & t\end{array}\right)



Just a yes or no will do... (if it's no, I am in trouble!)

Thanks!

Does it help you to point out that

\left(\begin{array}{cc}1 & t+1\\ 1 & t\end{array}\right)\left(\begin{array}{c}c_1 \\ c_2\end{array}\right)= \left(\begin{array}{c}c_1+ c_2(t+1) \\ c_1+ c_2t\end{array}\right)
 
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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