diff --git a/apps/shared/cartesian_function.cpp b/apps/shared/cartesian_function.cpp
index 463820a1c..e4b3beca0 100644
--- a/apps/shared/cartesian_function.cpp
+++ b/apps/shared/cartesian_function.cpp
@@ -255,7 +255,7 @@ CartesianFunction::CartesianFunctionRecordDataBuffer * CartesianFunction::record
 template<typename T>
 Coordinate2D<T> CartesianFunction::templatedApproximateAtParameter(T t, Poincare::Context * context) const {
   if (isCircularlyDefined(context) || t < tMin() || t > tMax()) {
-    return Coordinate2D<T>(NAN, NAN);
+    return Coordinate2D<T>(plotType() == PlotType::Cartesian ? t : NAN, NAN);
   }
   constexpr int bufferSize = CodePoint::MaxCodePointCharLength + 1;
   char unknown[bufferSize];