Systems of Differential Eq (Undetermined Coefficients)

In summary, the conversation is about solving a problem using the method of undetermined coefficients. The given matrix and vector are specified using latex and the complementary function is also provided. The person is seeking help in finding the particular solution due to the exponential form of F(t).
  • #1
champ2029
2
0
Hello guys,

I need help solving this problem.

Find the particular solution using method of undetermined coefficients:

X'=AX + F(t)

A= [4 ,1/3] <-- 1st row
[9 , 6] <-- 2nd row

F(t) = [-e^t,e^t]

The complementary function is Xc=c1[1,3]e^(3t) + c2[1,9]e^(7t)

Any help would be greatly appreciated!
 
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  • #2
Repost. Sorry if things aren't clear. Here are the given using latex

A=\begin{pmatrix}4 & 1/3\\ 9 & 6\end{pmatrix}

F(t)=\begin{pmatrix}-e^t\\ e^t\end{pmatrix}

##Xc=c1\begin{pmatrix}1\\ 3\end{pmatrix}e^3t + c2\begin{pmatrix} 1\\ 9\end{pmatrix}e^7t##

I'm having trouble finding the particular solution for the problem because F(t) is in exponential form. Please teach me how to approach this problem
 

Related to Systems of Differential Eq (Undetermined Coefficients)

What is the purpose of using undetermined coefficients in solving systems of differential equations?

The method of undetermined coefficients is used to find particular solutions for systems of differential equations by assuming a specific form for the solution and then solving for the coefficients that satisfy the equations. This allows for a more efficient and systematic approach to solving differential equations compared to simply guessing solutions.

What are the limitations of using undetermined coefficients for solving systems of differential equations?

Undetermined coefficients can only be used for linear systems of differential equations with constant coefficients. It also assumes that the particular solution has the same form as the non-homogeneous term in the equation. If these conditions are not met, other methods such as variation of parameters may need to be used.

How do I determine the particular solution using undetermined coefficients?

The particular solution is determined by plugging in the assumed form for the solution into the system of equations and solving for the coefficients. This may involve setting up a system of equations and using algebraic manipulations to solve for the coefficients.

Can undetermined coefficients be used to find general solutions for systems of differential equations?

No, undetermined coefficients can only be used to find particular solutions. To find the general solution for a system of differential equations, both the particular and homogeneous solutions must be combined.

Are there any tips for choosing the form of the particular solution when using undetermined coefficients?

It is best to choose a form for the particular solution that is similar to the non-homogeneous term in the equation. For example, if the non-homogeneous term is a polynomial, the particular solution should also be a polynomial. If the non-homogeneous term is a trigonometric function, the particular solution should also involve trigonometric functions. Additionally, it is important to make sure the assumed form does not overlap with the homogeneous solution.

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