diff --git a/poincare/src/sequence.cpp b/poincare/src/sequence.cpp
index 00f48111b..07aeb5159 100644
--- a/poincare/src/sequence.cpp
+++ b/poincare/src/sequence.cpp
@@ -43,6 +43,9 @@ Expression * Sequence::templatedApproximate(Context& context, AngleUnit angleUni
     delete result;
     delete expression;
     result = newResult;
+    if (result == nullptr) {
+      return new Complex<T>(Complex<T>::Float(NAN));
+    }
   }
   return result;
 }