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Student Support Forum: 'DSolve / NDSolve with matrices' topicStudent Support Forum > General > "DSolve / NDSolve with matrices"

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John Vacano
03/18/03 11:50am

Hello!

Perhaps somebody could help me with the following problem:

I want to solve a system of differential equations (eventually numerically, as they are going to be quite complex) using matrices for the definition of the function, like in the following basic example:

dmf[t_] := {{a[t], b[t]}, {c[t], d[t]}}
kmat = {{-kh, kr}, {kh, -kr}}

I could get it to work as follows:

DSolve[Flatten[dmf'[t]] == Flatten[dmf[t].kmat], Flatten[dmf[t]], t]

giving me the general solution with constants.

Trying to introduce starting conditions like:

DSolve[{Flatten[dmf'[t]] == Flatten[dmf[t].kmat],
Flatten[dmf[t]] == Flatten[{{1, 0}, {0, 0}}]}, Flatten[dmf[t]], t]

only gave me the following Error message:

DSolve::"nvld": "The description of the equations appears to be ambiguous or \
invalid."



What's wrong with this approach?


Thanks' a lot,

John

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Subject (listing for 'DSolve / NDSolve with matrices')
Author Date Posted
DSolve / NDSolve with matrices John Vacano 03/18/03 11:50am
Re: DSolve / NDSolve with matrices Forum Modera... 04/23/03 11:46am
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