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2015-09-07 00:31:53 +0100 | commented answer | Problems in solving eigenvalue equations with differential operators @nbruin Thank you very much! |

2015-09-06 10:13:10 +0100 | commented answer | Problems in solving eigenvalue equations with differential operators @nbruin. See my simplified example (I have posted it as another answer) |

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2015-09-06 10:12:07 +0100 | answered a question | Problems in solving eigenvalue equations with differential operators Take for example that $\hat A = a \frac{d^2}{dx^2}, a>0$ which leads to the eigenvalue equation $$\hat A f(x) = b f(x) \iff af''(x) = bf(x)$$ (I assume for simplicity that $b<0$). Using Code: Am I clear? |

2015-09-03 23:50:54 +0100 | asked a question | Problems in solving eigenvalue equations with differential operators Let's say we have a linear differential operator $\hat A = \sum_k a_k \frac {d^k} {dx^k}$ and we want to solve the eigenvalue equation $\hat A f(x) = a f(x)$ which is an ODE that we put in sage and outputs a solution $g(x)$. We now want to substitute $f(x)$ with $g(x)$ and simplify our expression in order to extract the eigenvalues of $\hat A$. The problem here is that I am not able to substitute the derivatives with my solution neither via |

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