Lagrange function

Algorithm for constructing the subsoil density distribution function considering its value on the surface

The conventional approach to constructing a three-dimensional distribution of the Earth's masses involves using Stokes constants incrementally up to a certain order. However, this study proposes an algorithm that simultaneously considers all of these constants, which could potentially provide a more efficient method. The basis for this is a system of equations obtained by differentiating the Lagrange function, which takes into account the minimum deviation of the three-dimensional mass distribution of the planet's subsoil from one-dimensional referential one.

On stability analysis study and strategies for optimal control of a mathematical model of hepatitis HCV with the latent state

In this work, we analyze a viral hepatitis C model.  This epidemic remains a major problem for global public health, in all communities, despite the efforts made.  The model is analyzed using the stability theory of systems of nonlinear differential equations.  Based on the results of the analysis, the proposed model has two equilibrium points: a disease-free equilibrium point $E_0$ and an endemic equilibrium point $E^{*}$.  We investigate the existence of equilibrium point of the model.  Furthermore, based on the indirect Lyapunov method, we study the local stability o