diff --git a/code/ex2-logistic regression/1. logistic_regression_v1.ipynb b/code/ex2-logistic regression/1. logistic_regression_v1.ipynb
index f1c36cde..eb35e39a 100644
--- a/code/ex2-logistic regression/1. logistic_regression_v1.ipynb	
+++ b/code/ex2-logistic regression/1. logistic_regression_v1.ipynb	
@@ -1556,7 +1556,7 @@
    "metadata": {},
    "source": [
     "# regularized gradient(正则化梯度)\n",
-    "$$\\frac{\\partial J\\left( \\theta  \\right)}{\\partial {{\\theta }_{j}}}=\\left( \\frac{1}{m}\\sum\\limits_{i=1}^{m}{\\left( {{h}_{\\theta }}\\left( {{x}^{\\left( i \\right)}} \\right)-{{y}^{\\left( i \\right)}} \\right)} \\right)+\\frac{\\lambda }{m}{{\\theta }_{j}}\\text{ }\\text{             for  j}\\ge \\text{1}$$"
+    "$$\\frac{\\partial J\\left( \\theta  \\right)}{\\partial {{\\theta }_{j}}}=\\left( \\frac{1}{m}\\sum\\limits_{i=1}^{m}{\\left( {{h}_{\\theta }}\\left( {{x}^{\\left( i \\right)}} \\right)-{{y}^{\\left( i \\right)}} \\right)} x_j^{(i)} \\right)+\\frac{\\lambda }{m}{{\\theta }_{j}}\\text{ }\\text{             for  j}\\ge \\text{1}$$"
    ]
   },
   {