Optimization of Economic Functions with two Variables

In addition to the mathematical notions for assigning stationary points with the help of the first partial derivatives of the two-variable function, we will classify these stationary points with the help of the second partial derivatives of the two-variable function, when the function f (x , y) reaches the maximum and when it reaches the minimum. The above notions will be applied to the profit optimization of any enterprise that produces two goods. We will also optimize an enterprise that sells some kind of product in different markets with price discrimination