Fix typo

Author: RamtinMoslemi

Previous_Semesters/1401_01/Jupyter_Notebooks/Chapter_01_Mathematics/Calculus_and_Optimization.ipynb

@@ -327,7 +327,7 @@
         "\t\t$$\\nabla f=(\\frac{\\partial f}{\\partial x_1},\\frac{\\partial f}{\\partial x_2})^T$$\n",
         "\t\tکه در آن\n",
         "\t\t$$\\frac{\\partial f}{\\partial x_1}=\\frac{\\partial (\\dfrac{1}{x_1}-4x_{2})}{\\partial x_1}=-\\dfrac{1}{x_1^2}\\quad ,\\quad \n",
-        "\t\t\\frac{\\partial f}{\\partial x_1}=\\frac{\\partial (\\dfrac{1}{x_1}-4x_{2})}{\\partial x_2}=-4$$\n",
+        "\t\t\\frac{\\partial f}{\\partial x_2}=\\frac{\\partial (\\dfrac{1}{x_1}-4x_{2})}{\\partial x_2}=-4$$\n",
         "\t\tبنابراین داریم\n",
         "\t\t$$\\nabla f=(-\\dfrac{1}{x_1^2},-4)^T$$\n",
         "\n",
@@ -799,4 +799,4 @@
       }
     }
   ]
-}
+}