Mathematical models can be described as a description of a system with mathematical language. This is done by introducing the system under study with a series of equations. Interpreter equations of the system are obtained based on the laws governing that system, boundary conditions, initial conditions and physical properties of the system under study. These models make it easier and faster to investigate the effect of various parameters on the system response. Once the mathematical model of a system is obtained, they can be solved analytically or numerically depending on the complexity of the equations. If the model presented is valid for a range of real numbers assigned to variables, it will be a continuous model, and if the model is valid for specific numbers in a range and for all real numbers in that range, it will be a model will be discrete. If the system does not respond to changes in time, the proposed model is called permanent. If the passage of time affects the response of the system, the proposed model is called a non-sustainable model.