Program2

代码说明：

  Differential equations (in this case is the ordinary differential equation) means containing one, two, and even high-differential equations unknowns. Is to solve the partial differential equations, mathematical equations based. There are many special functions, are not drawn to a number of functions or functions beyond the type of analytical solution of differential equations which define them. These special functions are important because they describe the nature of certain phenomena, for example, electronic activities, drum skin vibrations, pendulum swing, and so on.