释义 |
Frobenius MethodIf is an ordinary point of the Ordinary Differential Equation, expand in a Taylor Series about , letting
 | (1) |
Plug back into the ODE and group the Coefficients by Power. Now, obtain a Recurrence Relation for the thterm, and write the Taylor Series in terms of the s. Expansions for the first few derivatives are
If is a regular singular point of the Ordinary Differential Equation,
 | (5) |
solutions may be found by the Frobenius method or by expansion in a Laurent Series. In the Frobenius method, assumea solution of the form
 | (6) |
so that
Now, plug back into the ODE and group the Coefficients by Power to obtain a recursionFormula for the th term, and then write the Taylor Series in terms of the s. Equating the term to0 will produce the so-called Indicial Equation, which will give the allowed values of in the Taylor Series.
Fuchs's Theorem guarantees that at least one Power series solution will be obtained when applying the Frobeniusmethod if the expansion point is an ordinary, or regular, Singular Point. For a regularSingular Point, a Laurent Series expansion can also be used. Expand in aLaurent Series, letting
 | (10) |
Plug back into the ODE and group the Coefficients by Power. Now, obtain a recurrenceFormula for the th term, and write the Taylor Expansion in terms of the s.See also Fuchs's Theorem, Ordinary Differential Equation References
Arfken, G. ``Series Solutions--Frobenius' Method.'' §8.5 in Mathematical Methods for Physicists, 3rd ed. Orlando, FL: Academic Press, pp. 454-467, 1985.
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