diff --git a/Week 6/11 Parabolic PDEs: 1D Schrödinger Equation with Potential.ipynb b/Week 6/11 Parabolic PDEs: 1D Schrödinger Equation with Potential.ipynb
old mode 100644
new mode 100755
index 954d847..9540291
--- a/Week 6/11 Parabolic PDEs: 1D Schrödinger Equation with Potential.ipynb	
+++ b/Week 6/11 Parabolic PDEs: 1D Schrödinger Equation with Potential.ipynb	
@@ -160,12 +160,13 @@
     "\n",
     "with $\\delta_{ij} = 1 \\iff i = j$, and using the approximations $\\hbar = 1$, $m = 0.5$.\n",
     "\n",
-    "\n",
-    "finite differences for second derivative to get a tridiagonal matrix (one lower and one higher than diagonal)\n",
-    "then plot eigenvalues\n",
-    "no time component -> not complex?\n",
-    "energy should be real\n",
-    "eigenvectors squared should be normalized"
+    "$$\n",
+    "%finite differences for second derivative to get a tridiagonal matrix (one lower and one higher than diagonal)\n",
+    "%then plot eigenvalues\n",
+    "%no time component -> not complex?\n",
+    "%energy should be real\n",
+    "%eigenvectors squared should be normalized\n",
+    "$$"
    ]
   },
   {
@@ -201,7 +202,6 @@
     "        A tuple of the eigenvalues E and eigenfunctions \\Psi of the hamiltonian H.\n",
     "    \"\"\"\n",
     "    \n",
-    "    # TODO: Is n the dimensionality of Psi?\n",
     "    n = len(x)\n",
     "    h = x[1] - x[0]\n",
     "    \n",
@@ -286,7 +286,6 @@
     "fig = plt.figure(figsize=(12,12))\n",
     "\n",
     "for n in range(the_first_few):\n",
-    "    # TODO: Should SEQStat return normalized eigenfunctions?\n",
     "    # Normalize the found eigenfunctions using Riemann midpoint sums\n",
     "    prob_mass = np.sum((x[1:] - x[:-1])*(Psi[1:, n]**2 + Psi[:-1, n]**2)/2)\n",
     "    Psi[:, n] /= np.sqrt(prob_mass)\n",
@@ -383,7 +382,50 @@
     }
    },
    "source": [
-    "YOUR ANSWER HERE"
+    "To do the derivation of the Crank-Nicolson approach following $\\textit{Numerical Analysis}$ by Burden and Faires, we start from averaging our 'Forward-Difference method' at the jth step in t:\n",
+    "\n",
+    "$$\n",
+    "\\frac{w_{i,j+1}-w_{i,j}}{k}-\\alpha^2\\frac{w_{i+1,j}-2w_{i,j}+w_{i-1,j}}{h^2} = 0.\n",
+    "$$\n",
+    "\n",
+    "The local truncation error is:\n",
+    "\n",
+    "$$\n",
+    "\\tau_F = \\frac{k}{2}\\frac{\\partial^2 u}{\\partial t^2}(x_i,\\mu_j)+O(h^2).\n",
+    "$$\n",
+    "\n",
+    "We do the same for the 'Backward-Difference method' to get:\n",
+    "\n",
+    "$$\n",
+    "\\frac{w_{i,j+1}-w_{i,j}}{k}-\\alpha^2\\frac{w_{i+1,j+1}-2w_{i,j+1}+w_{i-1,j+1}}{h^2} = 0,\n",
+    "$$\n",
+    "\n",
+    "again with a local truncation error:\n",
+    "\n",
+    "$$\n",
+    "\\tau_B = -\\frac{k}{2}\\frac{\\partial^2 u}{\\partial t^2}(x_i,\\hat{u} _j)+O(h^2).\n",
+    "$$\n",
+    "\n",
+    "If we make the following assumption:\n",
+    "\n",
+    "$$\n",
+    "\\frac{\\partial^2 u}{\\partial t^2}(x_i,\\hat{\\mu}_j) \\approx \\frac{\\partial^2 u}{\\partial t^2}(x_i,\\mu_j),\n",
+    "$$\n",
+    "\n",
+    "Then we can get the 'averaged-difference method' to write:\n",
+    "\n",
+    "$$\n",
+    "\\frac{w_{i,j+1}-w_{i,j}}{k}-\\frac{\\alpha^2}{2}\\left[\\frac{w_{i+1,j}-2w_{i,j}+w_{i-1,j}}{h^2}+\\frac{w_{i+1,j+1}-2w_{i,j+1}+w_{i-1,j+1}}{h^2}\\right] = 0,\n",
+    "$$\n",
+    "\n",
+    "which now has an truncation error of the order $O(k^2+h^2)$. This is known as the Crank-Nicolson method and is represented in the form described above.\n",
+    "\n",
+    "For $\\lambda_1$ and $\\lambda_2$ we have the following expressions:\n",
+    "\n",
+    "$$\n",
+    "\\lambda_1 = \\alpha^2\\frac{k}{h^2}\\\\\n",
+    "\\lambda_2 = 1.\n",
+    "$$"
    ]
   },
   {
@@ -432,8 +474,7 @@
    "outputs": [],
    "source": [
     "def SEQDyn(x, t, V, f):\n",
-    "    # YOUR CODE HERE\n",
-    "    raise NotImplementedError()"
+    "    # YOUR CODE HERE"
    ]
   },
   {
@@ -457,8 +498,7 @@
    "source": [
     "# Animate your solution here ...\n",
     "\n",
-    "# YOUR CODE HERE\n",
-    "raise NotImplementedError()"
+    "# YOUR CODE HERE"
    ]
   },
   {
@@ -502,8 +542,7 @@
    },
    "outputs": [],
    "source": [
-    "# YOUR CODE HERE\n",
-    "raise NotImplementedError()"
+    "# YOUR CODE HERE"
    ]
   },
   {
@@ -567,7 +606,7 @@
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "Python 3",
+   "display_name": "Python 3 (ipykernel)",
    "language": "python",
    "name": "python3"
   },