A problem of a linear ODE with order $n$












1












$begingroup$


Is there an algorithm to solve this EDO in $mathbb{R}$?



begin{equation}
x^{(n)}(t) + x^{(n-1)}(t) + cdots + x''(t) + x'(t) + x(t) = 0
end{equation}



Or a more general ODE:



begin{equation}
sum_{k=0}^{n}a_kx^{(k)}(t) = f(t)
end{equation}



With ${a_k}_{kinmathbb{N}}$ a sucession belonging to $mathbb{R}$. I don't how to start.










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$endgroup$








  • 1




    $begingroup$
    This is probably the most "standard" $n$-th order ODE. Why is it weird?
    $endgroup$
    – Arctic Char
    Jan 1 at 3:27










  • $begingroup$
    @ArcticChar You are right, fixed
    $endgroup$
    – El Pasta
    Jan 1 at 3:28
















1












$begingroup$


Is there an algorithm to solve this EDO in $mathbb{R}$?



begin{equation}
x^{(n)}(t) + x^{(n-1)}(t) + cdots + x''(t) + x'(t) + x(t) = 0
end{equation}



Or a more general ODE:



begin{equation}
sum_{k=0}^{n}a_kx^{(k)}(t) = f(t)
end{equation}



With ${a_k}_{kinmathbb{N}}$ a sucession belonging to $mathbb{R}$. I don't how to start.










share|cite|improve this question











$endgroup$








  • 1




    $begingroup$
    This is probably the most "standard" $n$-th order ODE. Why is it weird?
    $endgroup$
    – Arctic Char
    Jan 1 at 3:27










  • $begingroup$
    @ArcticChar You are right, fixed
    $endgroup$
    – El Pasta
    Jan 1 at 3:28














1












1








1





$begingroup$


Is there an algorithm to solve this EDO in $mathbb{R}$?



begin{equation}
x^{(n)}(t) + x^{(n-1)}(t) + cdots + x''(t) + x'(t) + x(t) = 0
end{equation}



Or a more general ODE:



begin{equation}
sum_{k=0}^{n}a_kx^{(k)}(t) = f(t)
end{equation}



With ${a_k}_{kinmathbb{N}}$ a sucession belonging to $mathbb{R}$. I don't how to start.










share|cite|improve this question











$endgroup$




Is there an algorithm to solve this EDO in $mathbb{R}$?



begin{equation}
x^{(n)}(t) + x^{(n-1)}(t) + cdots + x''(t) + x'(t) + x(t) = 0
end{equation}



Or a more general ODE:



begin{equation}
sum_{k=0}^{n}a_kx^{(k)}(t) = f(t)
end{equation}



With ${a_k}_{kinmathbb{N}}$ a sucession belonging to $mathbb{R}$. I don't how to start.







ordinary-differential-equations






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share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Jan 1 at 3:29







El Pasta

















asked Jan 1 at 3:01









El PastaEl Pasta

46015




46015








  • 1




    $begingroup$
    This is probably the most "standard" $n$-th order ODE. Why is it weird?
    $endgroup$
    – Arctic Char
    Jan 1 at 3:27










  • $begingroup$
    @ArcticChar You are right, fixed
    $endgroup$
    – El Pasta
    Jan 1 at 3:28














  • 1




    $begingroup$
    This is probably the most "standard" $n$-th order ODE. Why is it weird?
    $endgroup$
    – Arctic Char
    Jan 1 at 3:27










  • $begingroup$
    @ArcticChar You are right, fixed
    $endgroup$
    – El Pasta
    Jan 1 at 3:28








1




1




$begingroup$
This is probably the most "standard" $n$-th order ODE. Why is it weird?
$endgroup$
– Arctic Char
Jan 1 at 3:27




$begingroup$
This is probably the most "standard" $n$-th order ODE. Why is it weird?
$endgroup$
– Arctic Char
Jan 1 at 3:27












$begingroup$
@ArcticChar You are right, fixed
$endgroup$
– El Pasta
Jan 1 at 3:28




$begingroup$
@ArcticChar You are right, fixed
$endgroup$
– El Pasta
Jan 1 at 3:28










1 Answer
1






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3












$begingroup$

A common method for linear ODE like this is to assume that the solution takes the form $y(t) = e^{lambda t}$. This will give you a polynomial in $lambda$, the solutions of which are called the eigenvalues. The solution will be something like
$$y(t) = c_1e^{lambda_1 t}+c_2e^{lambda_2 t} + ... + c_ne^{lambda_n t}.$$
For any complex $lambda$, you will have some portion of your solution being sinusoidal. You also need to adjust your solution for any repeated $lambda$.






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    1 Answer
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    1 Answer
    1






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    3












    $begingroup$

    A common method for linear ODE like this is to assume that the solution takes the form $y(t) = e^{lambda t}$. This will give you a polynomial in $lambda$, the solutions of which are called the eigenvalues. The solution will be something like
    $$y(t) = c_1e^{lambda_1 t}+c_2e^{lambda_2 t} + ... + c_ne^{lambda_n t}.$$
    For any complex $lambda$, you will have some portion of your solution being sinusoidal. You also need to adjust your solution for any repeated $lambda$.






    share|cite|improve this answer









    $endgroup$


















      3












      $begingroup$

      A common method for linear ODE like this is to assume that the solution takes the form $y(t) = e^{lambda t}$. This will give you a polynomial in $lambda$, the solutions of which are called the eigenvalues. The solution will be something like
      $$y(t) = c_1e^{lambda_1 t}+c_2e^{lambda_2 t} + ... + c_ne^{lambda_n t}.$$
      For any complex $lambda$, you will have some portion of your solution being sinusoidal. You also need to adjust your solution for any repeated $lambda$.






      share|cite|improve this answer









      $endgroup$
















        3












        3








        3





        $begingroup$

        A common method for linear ODE like this is to assume that the solution takes the form $y(t) = e^{lambda t}$. This will give you a polynomial in $lambda$, the solutions of which are called the eigenvalues. The solution will be something like
        $$y(t) = c_1e^{lambda_1 t}+c_2e^{lambda_2 t} + ... + c_ne^{lambda_n t}.$$
        For any complex $lambda$, you will have some portion of your solution being sinusoidal. You also need to adjust your solution for any repeated $lambda$.






        share|cite|improve this answer









        $endgroup$



        A common method for linear ODE like this is to assume that the solution takes the form $y(t) = e^{lambda t}$. This will give you a polynomial in $lambda$, the solutions of which are called the eigenvalues. The solution will be something like
        $$y(t) = c_1e^{lambda_1 t}+c_2e^{lambda_2 t} + ... + c_ne^{lambda_n t}.$$
        For any complex $lambda$, you will have some portion of your solution being sinusoidal. You also need to adjust your solution for any repeated $lambda$.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Jan 1 at 3:16









        D.B.D.B.

        1,2028




        1,2028






























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