diff --git a/src/main.cpp b/src/main.cpp
index e5adc9e7bcdf93ca3918fd1d47313c7a3d9a6117..55a0362a6e26b362c72a0818f2c6b63789645f18 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -216,7 +216,7 @@ int main(int argc, char *argv[])
      double pi = 4.*std::atan(1.);
      std::ofstream fout("comparaison E");
      for (size_t j=0; j<mesh.numberOfCells(); ++j) {
-       fout << xj[j][0] << ' ' << Ej[j] << ' ' << (std::cos(pi*xj[j][0]))*(std::cos(pi*xj[j][0]))*std::sin(pi*xj[j][0])*((pi*pi*pi)*0.5)*std::exp(-4.*pi*0.2) <<'\n';
+       fout << xj[j][0] << ' ' << Ej[j] << ' ' << (-(std::cos(pi*xj[j][0]))*(std::cos(pi*xj[j][0]))+(std::sin(pi*xj[j][0])*std::sin(pi*xj[j][0])))*(pi*0.5)*std::exp(-4.*pi*0.2) <<'\n';
      }
      }