diff --git a/chapter3/neumann_dirichlet_code.ipynb b/chapter3/neumann_dirichlet_code.ipynb
index ba0392cb..f043b527 100644
--- a/chapter3/neumann_dirichlet_code.ipynb
+++ b/chapter3/neumann_dirichlet_code.ipynb
@@ -16,7 +16,7 @@
     "-\\frac{\\partial u}{\\partial n}=g\n",
     "$$\n",
     "\n",
-    "is applied to the  remaining sides $y=0$ and $y=1$.\n",
+    "is applied to the remaining sides $y=0$ and $y=1$.\n",
     "\n",
     "## The PDE problem\n",
     "Let $\\Lambda_D$ and $\\Lambda_N$ denote parts of the boundary $\\partial \\Omega$ where the Dirichlet and Neumann conditions apply, respectively.\n",
diff --git a/chapter3/neumann_dirichlet_code.py b/chapter3/neumann_dirichlet_code.py
index 5a67cfba..f4adc919 100644
--- a/chapter3/neumann_dirichlet_code.py
+++ b/chapter3/neumann_dirichlet_code.py
@@ -23,7 +23,7 @@
 # -\frac{\partial u}{\partial n}=g
 # $$
 #
-# is applied to the  remaining sides $y=0$ and $y=1$.
+# is applied to the remaining sides $y=0$ and $y=1$.
 #
 # ## The PDE problem
 # Let $\Lambda_D$ and $\Lambda_N$ denote parts of the boundary $\partial \Omega$ where the Dirichlet and Neumann conditions apply, respectively.