A few fixes for the CoupledSpringMass notebook

ipython/CoupledSpringMassSystem.ipynb

@@ -33,7 +33,7 @@
       "no external forces, are $L_1$ and $L_2$.\n",
       "\n",
       "The masses are sliding on a surface that creates friction, so there are\n",
-      "two friction coefficients, b,,1,, and b,,2,,.\n",
+      "two friction coefficients, $b_1$ and $b_2$.\n",
       "\n",
       "The differential equations for this system are\n",
       "\n",
@@ -46,7 +46,9 @@
       "this to a system of first order differential equations. We introduce two\n",
       "variables\n",
       "\n",
-      "$y_1 = x_1'$, $y_2 = x_2'$\n",
+      "$y_1 = x_1'$\n",
+      "\n",
+      " $y_2 = x_2'$\n",
       "\n",
       "These are the velocities of the masses.\n",
       "\n",
@@ -67,7 +69,7 @@
       "equations (also known as a vector field). I have chosen to put the\n",
       "function that defines the vector field in its own module (i.e. in its\n",
       "own file), but this is not necessary. Note that the arguments of the\n",
-      "function are configured to be used with the function: the time t is the\n",
+      "function are configured to be used with the function odeint: the time t is the\n",
       "second argument."
      ]
     },
@@ -105,10 +107,9 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "Next, here is a script that uses to solve the equations for a given set\n",
+      "Next, here is a script that uses odeint to solve the equations for a given set\n",
       "of parameter values, initial conditions, and time interval. The script\n",
-      "prints the points in the solution to the terminal. Normally you will\n",
-      "redirect its output to a file."
+      "writes the points to the file 'two_springs.dat'."
      ]
     },
     {
@@ -172,7 +173,7 @@
      "cell_type": "markdown",
      "metadata": {},
      "source": [
-      "The following script uses Matplotlib to plot the solution generated by"
+      "The following script uses Matplotlib to plot the solution generated by the above script."
      ]
     },
     {