diff --git a/apps/graph/function.cpp b/apps/graph/function.cpp
index a69a0beda..3ef3aaf8f 100644
--- a/apps/graph/function.cpp
+++ b/apps/graph/function.cpp
@@ -1,5 +1,6 @@
 #include "function.h"
 #include <string.h>
+#include <math.h>
 
 namespace Graph {
 
@@ -85,6 +86,7 @@ float Function::approximateDerivative(float x, Context * context) const {
   float functionPlus = evaluateAtAbscissa(x + k_epsilon, context);
   float functionMinus = evaluateAtAbscissa(x - k_epsilon, context);
   float growthRate = (functionPlus - functionMinus)/(2*k_epsilon);
+  growthRate = roundf(growthRate/k_precision)*k_precision;
   return growthRate;
 }
 
diff --git a/apps/graph/function.h b/apps/graph/function.h
index d55778d2d..26884032e 100644
--- a/apps/graph/function.h
+++ b/apps/graph/function.h
@@ -27,6 +27,7 @@ public:
   float approximateDerivative(float x, Context * context) const;
 private:
   constexpr static float k_epsilon = 0.0001f;
+  constexpr static float k_precision = 0.01f;
   constexpr static int k_bodyLength = 255;
   char m_text[k_bodyLength];
   const char * m_name;