A unified analytical treatment for solving delay differential equations: exact solution

Volume 41, Issue 1, pp 25--33 https://dx.doi.org/10.22436/jmcs.041.01.03
Publication Date: August 29, 2025 Submission Date: April 18, 2025 Revision Date: May 24, 2025 Accteptance Date: June 21, 2025

Authors

E. R. El-Zahar - Department of Mathematics, College of Science and Humanities in Al-Kharj, Prince Sattam bin Abdulaziz University, P.O. Box 83, Al-Kharj 11942, Saudi Arabia. A. Ebaid - Department of Mathematics, Faculty of Science, University of Tabuk, P.O. Box 741, Tabuk 71491, Saudi Arabia. L. F. Seddek - Department of Mathematics, College of Science and Humanities in Al-Kharj, Prince Sattam bin Abdulaziz University, P.O. Box 83, Al-Kharj 11942, Saudi Arabia.


Abstract

The delay differential equations (DDEs) are widely used to explore various engineering and physical applications. An example of DDEs with proportional delays is known as the pantograph model which governs the current collection in electric trains. DDEs with constant delays also have different applications. This paper introduces a unified approach to analyze a class of first order DDEs under arbitrary history functions (HFs). The proposed approach assumes that the arbitrary HF \(\phi(t)\) can be represented as Maclaurin series with coefficients \(\phi_m, ~m\ge0\). Based on this assumption, the solution in each sub-interval of the problem's domain is obtained in explicit form in terms of the coefficients \(\phi_m\). Exact solutions are obtained for several examples subjected to history functions of different forms. Properties of the solution and its derivative are proved and examined theoretically. Existing results in the literature are derived from the current ones as special cases. In view of the obtained results, the exact solution of any first order linear delay differential equation can be directly determined once the coefficients \(\phi_m\) of the given history function is inserted into the standard solution. This reflects the advantage of the proposed approach over other techniques. Moreover, the suggested analysis can be easily extended to include higher order linear delay models.


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ISRP Style

E. R. El-Zahar, A. Ebaid, L. F. Seddek, A unified analytical treatment for solving delay differential equations: exact solution, Journal of Mathematics and Computer Science, 41 (2026), no. 1, 25--33

AMA Style

El-Zahar E. R., Ebaid A., Seddek L. F., A unified analytical treatment for solving delay differential equations: exact solution. J Math Comput SCI-JM. (2026); 41(1):25--33

Chicago/Turabian Style

El-Zahar, E. R., Ebaid, A., Seddek, L. F.. "A unified analytical treatment for solving delay differential equations: exact solution." Journal of Mathematics and Computer Science, 41, no. 1 (2026): 25--33


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