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Error bounds for the Liouville–Green (or WKB) approximation

Published online by Cambridge University Press:  24 October 2008

F. W. J. Olver
Affiliation:
National Physical LaboratoryTeddingtonMiddlesex

Abstract

Error bounds are derived and examined for approximate solutions in terms of elementary functions of the differential equations

in which u is a positive parameter, the functions f and p are free from singularities and p does not vanish. Bounds are also obtained for the remainder terms in the asymptotic expansions of the solutions in descending powers of u. The variable x ranges over a real interval, finite or infinite or over a region of the complex plane, bounded or unbounded.

Applications are made to parabolic cylinder functions of large orders, and modified Bessel functions of large orders.

Type
Research Article
Copyright
Copyright © Cambridge Philosophical Society 1961

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References

REFERENCES

(1)Liouville, J., Sur le développement des fonctions ou parties de fonotions en séries…. J. Math. Pures Appl. 2 (1837), 1635.Google Scholar
(2)Green, G., On the motion of waves in a variable canal of small depth and width. Trans. Camb. Phil. Soc. 6 (1837), 457–62.Google Scholar
(3)Wentzel, G., Eine Verallgemeinerung der Quantenbedingungen für die Zwecke der Wellenmechanik. Z. Phys. 38 (1926), 518–29.CrossRefGoogle Scholar
(4)Kramers, H. A., Wellenmeohanik und halbzahlige Quantisierung. Z. Phys. 39 (1926), 828–40.CrossRefGoogle Scholar
(5)Brillouin, L., Remarques sur la Méchanique Ondulatoire. J. Phys. Radium, 7 (1926), 353–68.CrossRefGoogle Scholar
(6)Erdélyi, A., Asymptotic solution of differential equations with transition points. Proc. Int. Congr. Math. Amsterdam, 3 (1954), 92101.Google Scholar
(7)Jeffreys, H., On certain approximate solutions of linear differential equations of the second order. Proc. Lond. Math. Soc. 23 (19241925), 428–36.Google Scholar
(8)Jeffreys, H., On approximate solutions of linear differential equations. Proc. Camb. Phil. Soc. 49 (1953), 601–11.CrossRefGoogle Scholar
(9)Gans, R., Fortpflanzung des Lichts durch ein inhomogenes Medium. Ann. Phys., Lpz., 47 (1915), 709–36.CrossRefGoogle Scholar
(10)Blumenthal, O., Uber asymptotische Integration linearer Differentialgleichungen, mit Anwendung auf eine asymptotische Theorie der Kugelfunktionen. Arch. Math. Phys., Lpz., 19 (1912), 136–74.Google Scholar
(11)Horn, J., Ueber eine lineare Differentialgleichung zweiter Ordnung mit einem willkürlichen Parameter. Math. Ann. 52 (1899), 271–92.CrossRefGoogle Scholar
(12)Olver, F. W. J., Uniform asymptotic expansions of solutions of linear second-order differential equations for large values of a parameter. Phil. Trans. A, 250 (1958), 479517.Google Scholar
(13)Titchmarsh, E. C., The theory of functions, 2nd ed. (Oxford, 1939).Google Scholar
(14)Olver, F. W. J., The asymptotic expansion of Bessel functions of large order. Phil. Trans. A, 247 (1954), 328–68.Google Scholar
(15)Olver, F. W. J., Error bounds for Airy-function expansions in turning-point problems. (In preparation.)Google Scholar
(16)Erdélyi, A., Singular Volterra integral equations and their use in asymptotic expansions. U.S. Army Mathematics Research Center Technical Summary Report, No. 194 (Madison, Wisconsin, 1960).Google Scholar
(17)Wintner, A., The Schwarzian derivative and the approximation method of Brillouin. Quart. Appl. Math. 16 (1958), 82–6.CrossRefGoogle Scholar
(18)Olver, F. W. J., Uniform asymptotic expansions for Weber parabolic cylinder functions of large orders. J. Res. Nat. Bur. Stand. 63 B (1959), 131–69.CrossRefGoogle Scholar
(19)Olver, F. W. J., Tables for Bessel functions of moderate or large orders. Math. Tab. Nat. Phys. Lab. 6 (London: H. M. Stationery Office, In the Press).Google Scholar