[lesson2] Removing most mentions of .

Author: Murilo M. Marinho

cheat_sheet.ipynb

@@ -80,6 +80,16 @@
     "from math import pi, sin, cos"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Suggested exercises\n",
+    "1. What about an RRR robot?\n",
+    "2. What about if the robot had `n` degrees-of-freedom? \n",
+    "3. What if the robot is RP, that is, has a prismatic joint?"
+   ]
+  },
   {
    "attachments": {
     "4A.png": {
@@ -475,19 +485,6 @@
     "else:\n",
     "    raise Exception(\"The numpy and spatialmath results are not the same for H_A2\")"
    ]
-  },
-  {
-   "cell_type": "markdown",
-   "metadata": {},
-   "source": [
-    "\n",
-    "\n",
-    "# Further study\n",
-    "\n",
-    "1. What about if the robot had 3 degrees-of-freedom, that is RRR?\n",
-    "2. What about if the robot had n degrees-of-freedom? Would it be much more complicated to solve?\n",
-    "3. What if the robot has one or more prismatic joints?"
-   ]
   }
  ],
  "metadata": {