diff --git a/apps/graph/graph/extremum_graph_controller.cpp b/apps/graph/graph/extremum_graph_controller.cpp
index 999b211d9..6044d07f9 100644
--- a/apps/graph/graph/extremum_graph_controller.cpp
+++ b/apps/graph/graph/extremum_graph_controller.cpp
@@ -16,11 +16,7 @@ const char * MinimumGraphController::title() {
 }
 
 Coordinate2D<double> MinimumGraphController::computeNewPointOfInterest(double start, double step, double max, Poincare::Context * context) {
-  // TODO The following three lines should be factored.
-  constexpr int bufferSize = CodePoint::MaxCodePointCharLength + 1;
-  char unknownX[bufferSize];
-  Poincare::SerializationHelper::CodePoint(unknownX, bufferSize, UCodePointUnknownX);
-  return Shared::PoincareHelpers::NextMinimum(functionStore()->modelForRecord(m_record)->expressionReduced(context), unknownX, start, step, max, context);
+  return functionStore()->modelForRecord(m_record)->nextMinimumFrom(start, step, max, context);
 }
 
 MaximumGraphController::MaximumGraphController(Responder * parentResponder, GraphView * graphView, BannerView * bannerView, Shared::InteractiveCurveViewRange * curveViewRange, Shared::CurveViewCursor * cursor) :
@@ -33,11 +29,7 @@ const char * MaximumGraphController::title() {
 }
 
 Coordinate2D<double> MaximumGraphController::computeNewPointOfInterest(double start, double step, double max, Poincare::Context * context) {
-  // TODO The following three lines should be factored.
-  constexpr int bufferSize = CodePoint::MaxCodePointCharLength + 1;
-  char unknownX[bufferSize];
-  Poincare::SerializationHelper::CodePoint(unknownX, bufferSize, UCodePointUnknownX);
-  return Shared::PoincareHelpers::NextMaximum(functionStore()->modelForRecord(m_record)->expressionReduced(context), unknownX, start, step, max, context);
+  return functionStore()->modelForRecord(m_record)->nextMaximumFrom(start, step, max, context);
 }
 
 }
diff --git a/apps/shared/cartesian_function.cpp b/apps/shared/cartesian_function.cpp
index bf3ebcf54..cdeea46cc 100644
--- a/apps/shared/cartesian_function.cpp
+++ b/apps/shared/cartesian_function.cpp
@@ -274,6 +274,14 @@ Coordinate2D<T> CartesianFunction::templatedApproximateAtParameter(T t, Poincare
       PoincareHelpers::ApproximateWithValueForSymbol(e.childAtIndex(1), unknown, t, context));
 }
 
+Coordinate2D<double> CartesianFunction::nextMinimumFrom(double start, double step, double max, Context * context) const {
+  return nextPointOfInterestFrom(start, step, max, context, [](Expression e, char * symbol, double start, double step, double max, Context * context) { return PoincareHelpers::NextMinimum(e, symbol, start, step, max, context); });
+}
+
+Coordinate2D<double> CartesianFunction::nextMaximumFrom(double start, double step, double max, Context * context) const {
+  return nextPointOfInterestFrom(start, step, max, context, [](Expression e, char * symbol, double start, double step, double max, Context * context) { return PoincareHelpers::NextMaximum(e, symbol, start, step, max, context); });
+}
+
 Coordinate2D<double> CartesianFunction::nextRootFrom(double start, double step, double max, Context * context) const {
   return nextPointOfInterestFrom(start, step, max, context, [](Expression e, char * symbol, double start, double step, double max, Context * context) { return Coordinate2D<double>(PoincareHelpers::NextRoot(e, symbol, start, step, max, context), 0.0); });
 }
diff --git a/apps/shared/cartesian_function.h b/apps/shared/cartesian_function.h
index 2b3e36b50..94f5d9d42 100644
--- a/apps/shared/cartesian_function.h
+++ b/apps/shared/cartesian_function.h
@@ -57,9 +57,12 @@ public:
   void setTMax(float tMax);
   float rangeStep() const override { return plotType() == PlotType::Cartesian ? NAN : (tMax() - tMin())/k_polarParamRangeSearchNumberOfPoints; }
 
-  // Cartesian calculation
-  Poincare::Coordinate2D<double> nextIntersectionFrom(double start, double step, double max, Poincare::Context * context, CartesianFunction * f) const;
+  // Extremum
+  Poincare::Coordinate2D<double> nextMinimumFrom(double start, double step, double max, Poincare::Context * context) const;
+  Poincare::Coordinate2D<double> nextMaximumFrom(double start, double step, double max, Poincare::Context * context) const;
+  // Roots
   Poincare::Coordinate2D<double> nextRootFrom(double start, double step, double max, Poincare::Context * context) const;
+  Poincare::Coordinate2D<double> nextIntersectionFrom(double start, double step, double max, Poincare::Context * context, CartesianFunction * f) const;
 private:
   constexpr static float k_polarParamRangeSearchNumberOfPoints = 100.0f; // This is ad hoc, no special justification
   typedef Poincare::Coordinate2D<double> (*ComputePointOfInterest)(Poincare::Expression e, char * symbol, double start, double step, double max, Poincare::Context * context);