fixed numpy

exercises/matrices-numpy/matrices-numpy-solution.ipynb

@@ -1704,7 +1704,7 @@
     "\n",
     "Let's make an attempt of substitution, as an example we first try dividing a number by positive zero (even if math teachers tell us such divisions are forbidden) - what will we ever get??\n",
     "\n",
-    "$ \\frac{5.0}{0.0}= ???$\n",
+    "$\\frac{5.0}{0.0}=???$\n",
     "\n",
     "In Numpy terms, we might write like this to box everything in arrays:"
    ]
@@ -1873,7 +1873,7 @@
     "\n",
     "**WARNING: the following may cause severe convulsions and nausea.**\n",
     "\n",
-    "During clinical trials, both mathematically inclined and math-averse patients have experienced such symptoms, for different reasons.\n",
+    "During clinical trials, both mathematically inclined and math-averse patients have experienced illness, for different reasons which are currently being investigated.\n",
     "\n",
     "</div>\n",
     "\n",
@@ -1898,56 +1898,6 @@
     "```"
    ]
   },
-  {
-   "cell_type": "code",
-   "execution_count": 62,
-   "metadata": {
-    "scrolled": true
-   },
-   "outputs": [
-    {
-     "data": {
-      "text/plain": [
-       "False"
-      ]
-     },
-     "execution_count": 62,
-     "metadata": {},
-     "output_type": "execute_result"
-    }
-   ],
-   "source": [
-    "[np.nan, np.inf] == [-np.nan, np.inf]"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 63,
-   "metadata": {},
-   "outputs": [
-    {
-     "name": "stderr",
-     "output_type": "stream",
-     "text": [
-      "/home/da/Da/bin/anaconda3/lib/python3.7/site-packages/ipykernel_launcher.py:1: RuntimeWarning: invalid value encountered in sqrt\n",
-      "  \"\"\"Entry point for launching an IPython kernel.\n"
-     ]
-    },
-    {
-     "data": {
-      "text/plain": [
-       "nan"
-      ]
-     },
-     "execution_count": 63,
-     "metadata": {},
-     "output_type": "execute_result"
-    }
-   ],
-   "source": [
-    "np.sqrt(-1)*np.sqrt(-1)"
-   ]
-  },
   {
    "cell_type": "markdown",
    "metadata": {},