http://latex.codecogs.com/png.latex?sh(x)=\frac{ex+e{-x}}{2}}
![02] http://latex.codecogs.com/png.latex?C_n^k=\frac{n(n-1)\ldots(n-k+1)}{k!}
![](http://latex.codecogs.com/gif.latex?\frac{\partial J}{\partial \theta_k{(j)}}=\sum_{i:r(i,j)=1}{\big((\theta{(j)})Tx{(i)}-y{(i,j)}\big)x_k{(i)}}+\lambda \theta_k^{(j)})