diff --git a/profiling/numerical_integration.py b/profiling/numerical_integration.py
index 8ed588c..00842d5 100644
--- a/profiling/numerical_integration.py
+++ b/profiling/numerical_integration.py
@@ -8,7 +8,7 @@ def numerical_integration(f, a, b, n):
         dx = (b - a) / n
         x = a + (i + 0.5) * dx
         y = f(x)
-        s = s + [y * dx]
+        s.append(y * dx)
     return s