In article, it was dealed with the model of ideal mixing and idealized flow entering the reactor which instantly distributed throughout the volume as a result of the complete (ideal) mixing of the medium particles. It was used the half-division method (dichotomy method) of the intervals in the MathCAd medium. It was used the system of algebraic equations of material and thermal equilibrium. We have determined the optimal concentration of the components of the reaction in the stationary mode, Optimization of the problem of the output of the target product for the isothermal thermal regime and the chemical process gave the possibility to obtain the maximum value of the function at given points and to calculate the residence time of the substances in the reaction at each reaction interval depending on the change of the concentration of the reactant substance for the chosen chemical process and the given coefficients.