diff --git a/ISC_421_Controle_4_Saroukhanian_Iliya.py b/ISC_421_Controle_4_Saroukhanian_Iliya.py
index fcbc8f15a7b380f49e01efda2631f90d1ab0478d..51eace78aef6f3fbc23cb82476d03841740182e1 100644
--- a/ISC_421_Controle_4_Saroukhanian_Iliya.py
+++ b/ISC_421_Controle_4_Saroukhanian_Iliya.py
@@ -155,7 +155,7 @@ print(f"valeur de la fonction en a et b:  {SD.f(SD.a), SD.f(SD.b)}")
 
 
 def errmax_taylor(plot_range, eval_pt):
-    return (SD.Maximal_derivatives_values[len(SD.Maximal_derivatives_values) - 1] /
+    return (SD.Maximal_derivatives_values[-1] /
             math.factorial(len(SD.Maximal_derivatives_values) + 1)) * \
         (plot_range - eval_pt)**(len(SD.Maximal_derivatives_values) + 1)