中文说明：资源描述机器学习的代码，关于线性拟合的，有代价函数，有梯度下降，大家可以来看看，不过我写的这个可能适合菜鸟看，太简单了，也可能有错误，欢迎大家来批评指正
English Description：
Application backgroundMachine learning code, on the linear fitting, there is a cost function, there is a gradient descent, we can see, but I write this may be suitable for the rookie, too simple, there may be errors, welcome to criticize me