It is very important that it stands out from the way that has been done in this article, other applications that the study of the derivative has different from what is traditionally explained, for example in my case that I study food engineering, I have only seen the part of exercise in what refers to calculation, so I think this point of analysis that you do in this publication seems very important. Congratulations, continue publishing as well, and follow the success Hive account@carlos84. Regards