The system has a higher order is quite common in chemical engineering. I often meet for a model of the system with order higher than the system with the order under format (No. 1 or No. 2) An error related simplified this is normal, is uncertain. in the model (for error. As in a number of significant coefficients, the hypothesis would not be in the form altogether, etc.) and the exact format solution with a higher order may. Determined and fixed by means of a system similar to the first order and second order.