采用bp神经网络对函数y=sin（x）进行训练，然后用测试集对训练的函数进行测试，也就是函数逼近sin（x)的曲线-Bp neural network using the function y = sin (x) for training, and then use the test set to test the training function, that is, function approximation sin (x) curve

用代码（非工具箱）实现BP神经网络对含有随机噪声的sin函数的逼近(The approximation of sin function with random noise by BP neural network with code (non toolbox))