数学建模用的模型大家一起分享，我们共同学习共同提高。谢谢您的来访。-Mathematical Modeling of the model used to share together, learn together to enhance our common. Thank you for your visit.

差分 微分模型的代码,很好用，学习很快。可尝试学习。-Differential differential model code, useful, learning quickly. You can try to learn.