Economics-Ideas of Marginal

This is my first post about economics. I think one of the most significant ideas in economics is the idea of “marginal”. Marginal corresponds to the idea of “derivatives and differential” in mathematics. In real life, people won’t think on the whole but rather about what would happen if they made a single choice or made a small difference. In terms of economics, the terminology of rational producer is the one who aims at maximization of profit. Technically, a rational producer operates in the stage of ‘diminishing returns to a factor’ where the fixed factor is fully utilized and the efficiency of the factors is the maximum. Through these methods of “marginal”, and some quantification methods (quantifying and using parameters help us to describe details involved in making decisions), we can predict a person’s behavior to a certain degree. In conclusion, the effectiveness of the prediction depends on the completeness of the medals and the validity of your parameters. And one disappointing fact is that there are no totally precise and robust models and systems.