diff --git a/extra_autodiff.ipynb b/extra_autodiff.ipynb
index 6ef643d..ca8a0c7 100644
--- a/extra_autodiff.ipynb
+++ b/extra_autodiff.ipynb
@@ -235,7 +235,7 @@
    "outputs": [],
    "source": [
     "def d2f(x, y):\n",
-    "    return [gradients(dfdx, [3., 4.]), gradients(dfdy, [3., 4.])]"
+    "    return [gradients(dfdx, [x, y]), gradients(dfdy, [x, y])]"
    ]
   },
   {