Note on The derivation of EOQ/EPQ inventory models with two backorders costs using analytic geometry and algebra

This study examines the paper of Cardenas-Barron, entitled The derivation of EOQ/EPQ inventory models with two backorders costs using analytic geometry and algebra. that was published in Applied Mathematical Modelling at 2011 to point out it contains questionable results. The algebraic geometry and algebra applied by Cardenas-Barron [2] violated the rule of the arithmetic-geometric mean (AGM) mentioned by Cardenas-Barron [74]. Moreover, we point out Sphicas [1] had already solved this kind of EOQ and EPQ models using algebraic methods. (C) 2019 Published by Elsevier Inc.