diff --git a/notebooks/problem0031.ipynb b/notebooks/problem0031.ipynb
index c3fedc8..bd050fa 100644
--- a/notebooks/problem0031.ipynb
+++ b/notebooks/problem0031.ipynb
@@ -44,7 +44,7 @@
     "\n",
     "The seemingly trivial series $(1, 1, 1, 1, \\ldots)$ has an equally simple generating function\n",
     "$$1 + x + x^2 + x^3 + x^4 + \\cdots$$\n",
-    "which converges to $\\frac{1}{1-x}$ for $-1 < x < 1$. (Note that we don't really care about the interval of convergence, because we're not going to be evaluating this function directly. Here, $x$ is an [indeterminate variable](https://en.wikipedia.org/wiki/Indeterminate_(variable)).)\n",
+    "which converges to $\\frac{1}{1-x}$ for $-1 < x < 1$. (Note that we don't really care about the interval of convergence, because we're not going to be evaluating this function directly. Here, $x$ is called an indeterminate.)\n",
     "\n",
     "If this is your first time seeing generating functions, it's probably not obvious how they can help us solve this problem. Let's look at some related, simpler problems to lead us towards understanding.\n",
     "\n",