remove incompatible latex symbol

Author: HumphreyYang

content/lectures/cass_koopmans_2.ipynb

@@ -439,7 +439,7 @@
     "or\n",
     "\n",
     "$$\n",
-    "\\sum_{t=0}^T q^0_t  \\left(c_t + (k_{t+1} -(1-\\delta)k_t)\\right) \\leq \\sum_{t=0}^T q^0_t(w_t 1 + \\eta_t k_t)  \\\n",
+    "\\sum_{t=0}^T q^0_t  \\left(c_t + (k_{t+1} -(1-\\delta)k_t)\\right) \\leq \\sum_{t=0}^T q^0_t(w_t 1 + \\eta_t k_t)\n",
     "$$\n",
     "\n",
     "The household faces price system $ \\{q^0_t, w_t, \\eta_t\\} $ as a price-taker and  chooses an allocation to solve the constrained optimization problem:\n",