{"id":6021,"date":"2026-01-21T11:44:30","date_gmt":"2026-01-21T11:44:30","guid":{"rendered":"https:\/\/izvestiyakbncran.ru\/?page_id=6021"},"modified":"2026-04-13T13:10:26","modified_gmt":"2026-04-13T12:10:26","slug":"27-6-3-en","status":"publish","type":"page","link":"https:\/\/izvestiyakbncran.ru\/index.php\/en\/27-6-3-en\/","title":{"rendered":"27.6.3 En"},"content":{"rendered":"\n

On inversion of Laplace transform of function, involving hyperbolic tangen<\/strong>t<\/h1>\n\n\n\n

F.G. Khushtova<\/strong><\/p>\n\n\n\n

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Upload the full text<\/strong><\/strong><\/p>\n\n\n\n

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Abstract<\/strong><\/strong>. <\/em>The paper examines the inverse of the Laplace transform with a hyperbolic tangen function. This function arises when solving a boundary value problem in a bounded domain governed by the heat
equation, subject to boundary conditions of the second and third kind.
Aim<\/strong>. To determine the inverse Laplace transform of a function that emerges from solving a boundary value problem, specifically a second or third type condition, associated with the heat equation.
Results<\/strong>. Using the residue theorem and the theory of a complex variable functions, we derive the inverse transform, suitable for large and small time values. In the first case, the inverse transform is expressed as a series of exponential functions with constant coefficients; in the second case, as a series of Laplace convolutions of special functions.
Conclusion and deduction<\/strong>. The derived results constitute a basis for constructing a solution to the boundary value problem for the heat equation in a bounded domain with a second-order condition on one of the boundaries and a third-order condition on the other, in a form suitable for small time values. In the context of mathematical physics, a solution to a similar problem is derived via separation of variables suitable for characterizing heat transfer processes for large time values. However, this proves inconvenient given sufficiently small temporal values, due to poor convergence properties pertaining to the Fourier series expansion involving eigenfunctions of the problem.<\/p>\n\n\n\n

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Keywords<\/strong>:<\/em><\/strong> Laplace transform, residue theorem, Jordan’s lemma, hyperbolic tangent, probability integral, Laguerre polynomials<\/p>\n\n\n\n

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For citation<\/strong>.<\/strong> Khushtova F.G. On inversion of Laplace transform of function, involving hyperbolic tangent. News of the Kabardino-Balkarian Scientific Center of RAS<\/em>. 2025. Vol. 27. No. 6. Pp. 30\u201338. DOI: 10.35330\/1991-6639-2025-27-6-30-38<\/p>\n\n\n\n

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R<\/strong>eferences<\/summary>\n
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  1. Remizova O.I., Sosnin M.L. Operational method for constructing Green\u2019s functions for small times corresponding to the solution to the boundary value problems for transfer equations of parabolic type. Fine Chemical Technologies. 2011. Vol. 6. No. 3. Pp. 116\u2013119. EDN: OHJVKN. (In Russian)<\/li>\n\n\n\n
  2. Ditkin V.A., Prudnikov A.P. Integral’nye preobrazovaniya i operacionnoe ischislenie
    [Integral transforms and operational calculus]. Moscow: Fizmatlit, 1961. (In Russian)<\/li>\n\n\n\n
  3. Sveshnikov A.G., Tihonov A.N. The theory of functions of a complex variable. Moscow: MIR PUBLISHERS, 1978. (In Russian)<\/li>\n\n\n\n
  4. Doetsch G. Guide to the applications of the Laplace and Z-transforms. London: Van Nostrand Reinhold Company, 1971.<\/li>\n\n\n\n
  5. Galitsyn A.S., Zhukovsky A.N. Integral’nye preobrazovaniya i special’nye funkcii v zadachah teploprovodnosti [Integral transforms and special functions in heat conduction problems]. Kiev: Naukova Dumka, 1976. (In Russian)<\/li>\n\n\n\n
  6. Bateman G., Erdelyi A. Tablicy integral’nyh preobrazovaniy [Tables of integral transforms]. Moscow: Nauka, 1969. Vol. 1. 344 p. (In Russian)<\/li>\n\n\n\n
  7. Bateman G., Erdelyi A. Vysshie transcendentnye funkcii [Higher transcendental functions]. Vol. 2. Moscow: Nauka, 1966. (In Russian)<\/li>\n\n\n\n
  8. Lebedev N.N. Special functions and their applications. Prentice-Hall, Inc, 1965.<\/li>\n\n\n\n
  9. Carslaw H.S., Jaeger J.C. Conduction of heat in solids. Oxford: Oxford University Press. 1959.<\/li>\n\n\n\n
  10. Lykov A.V. Teoriya teploprovodnosti [Theory of Heat Conduction]. Moscow: Vysshaya shkola, 1967. (In Russian)<\/li>\n<\/ol>\n<\/details>\n\n\n\n
    Information about the author<\/strong>s<\/summary>\n
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    Fatima G. Khushtova<\/strong>, Candidate of Physics and Mathematics, Researcher, Department of Fractional calculus, Institute of Applied Mathematics and Automation \u2013 branch of the Kabardino-Balkarian Scientific Center of the Russian Academy of Sciences;
    89 A, Shortanov street, Nalchik, 360000, Russia;
    khushtova@yandex.ru, ORCID: https:\/\/orcid.org\/0000-0003-4088-3621, SPIN-code: 6803-4959<\/p>\n\n\n\n

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    <\/p>\n","protected":false},"excerpt":{"rendered":"

    On inversion of Laplace transform of function, involving hyperbolic tangent F.G. Khushtova Upload the full text Abstract. The paper examines the inverse of the Laplace transform with a hyperbolic tangen function. 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