MATHEMATICS, cilt.11, sa.3, ss.697-719, 2023 (SCI-Expanded)
In this article, we present a study about the evolution of the COVID-19 pandemic in
Turkey. The modelling of a new virus named SARS-CoV-2 is considered by an SIR model consisting
of a nonlinear system of differential equations. A collocation approach based on the Pell–Lucas
polynomials is studied to get the approximate solutions of this model. First, the approximate solution
in forms of the truncated Pell–Lucas polynomials are written in matrix forms. By utilizing the
collocation points and the matrix relations, the considered model is converted to a system of the
nonlinear algebraic equations. By solving this system, the unknown coefficients of the assumed
Pell–Lucas polynomial solutions are determined, and so the approximate solutions are obtained.
Secondly, two theorems about the error analysis are given and proved. The applications of the
methods are made by using a code written in MATLAB. The parameters and the initial conditions
of the model are determined according to the reported data from the Turkey Ministry of Health.
Finally, the approximate solutions and the absolute error functions are visualized. To demonstrate the
effectiveness of the method, our approximate solutions are compared with the approximate solutions
obtained by the Runge–Kutta method. The reliable results are obtained from numerical results and
comparisons. Thanks to this study, the tendencies of the pandemic can be estimated. In addition, the
method can be applied to other countries after some necessary arrangements.