Collection of Open Letters to Iranian Patriotic People and Economists in Connection with the 2018 Crisis;

In connection with the theory of growth and business cycles and its relation with mathematical functions;

Economic effectiveness, social effectiveness, environmental effectiveness is a measure or process that leads to efficiency in growth theory and business cycles and maximizes management performance; Based on mathematical functions we will have; In the case of the cubic function

In the equation y = 0 because it is quadratic in the equation c/a<0 . The equation always has two different answers with various signs, so there is always a maximum and a minimum for the function.