用C语言设计BP神经网络并拟合函数1.y=sinx,x :[0,2pi) 2.y=(x1)^2+(x2)^2+(x1)*(x2) ,x1,x2:[0,1)-With C-BP neural network design and fitting function 1.y = sinx, x: [0,2 pi) 2.y = (x1) ^ 2+ (x2) ^ 2+ (x1)* (x2), x1, x2: [0,1)