A note on the economic lot size of the integrated vendor–buyer inventory system derived without derivatives

Numerous researches on the integrated production inventory models use differential calculus to solve the multi-variable problems. This study simplifies the solution procedure using a simple algebraic method to solve the multi-variable problems. As a result, students who are unfamiliar with calculus may be able to understand the solution procedure with ease. This paper refers to the approach by Grubbström and Erdem and extends the model by Yang and Wee to derive an algebraic method to solve the three decision variables of the proposed model.