Fix typo in density matrix designation on tutorials/circuits/1_getting_started_with_qiskit.ipynb

Author: zodiacfireworks

tutorials/circuits/1_getting_started_with_qiskit.ipynb

@@ -297,7 +297,8 @@
    "source": [
     "Qiskit also provides a visualization toolbox to allow you to view these results.\n",
     "\n",
-    "Below, we use the visualization function to plot the real and imaginary components of the state density matrix $\rho$."
+    "Below, we use the visualization function to plot the real and imaginary components of the state density matrix $\n",
+    "\\rho$."
    ]
   },
   {
@@ -630,7 +631,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.7.7"
+   "version": "3.8.2"
   },
   "varInspector": {
    "cols": {