diff --git a/poincare/src/derivative.cpp b/poincare/src/derivative.cpp
index d4159e606..0d139fd73 100644
--- a/poincare/src/derivative.cpp
+++ b/poincare/src/derivative.cpp
@@ -176,8 +176,12 @@ Expression Derivative::shallowReduce(ExpressionNode::ReductionContext reductionC
     return *this;
   }
   /* Updates the value of derivand, because derivate may call
-   * replaceWithInplace on it */
-  derivand = childAtIndex(0);
+   * replaceWithInplace on it.
+   * We need to reduce the derivand here before replacing the symbol : the
+   * general formulas used during the derivation process can create some nodes
+   * that are not defined for some values (e.g. log), but that would disappear
+   * at reduction. */
+  derivand = childAtIndex(0).deepReduce(reductionContext);
   /* Deep reduces the child, because derivate may not preserve its reduced
    * status. */
 
diff --git a/poincare/test/derivative.cpp b/poincare/test/derivative.cpp
index 1621c893b..89e9a1aee 100644
--- a/poincare/test/derivative.cpp
+++ b/poincare/test/derivative.cpp
@@ -64,4 +64,6 @@ QUIZ_CASE(poincare_derivative_approximation) {
   assert_reduces_for_approximation("diff(abs(x),x,123)", "1");
   assert_reduces_for_approximation("diff(abs(x),x,-2.34)", "-1");
   assert_reduces_for_approximation("diff(abs(x),x,0)", Undefined::Name());
+
+  assert_reduces_for_approximation("diff(1/x,x,-2)", "-1/4");
 }