git-svn-id: https://svn.dealii.org/trunk@23135 0785d39b-7218-0410-832d-ea1e28bc413d

diff --git a/deal.II/examples/step-38/doc/intro.dox b/deal.II/examples/step-38/doc/intro.dox
index 4fb138d76b9c6be3b381ebba1b4ff1b0e2fa4c81..bcdf18fee1a731d69cca5a94e07908313ee83e4c 100644 (file)
--- a/deal.II/examples/step-38/doc/intro.dox
+++ b/deal.II/examples/step-38/doc/intro.dox
@@ -192,10 +192,8 @@ solution. Since the solution function and its numerical approximation are only
 defined on the manifold, the obvious definition of this error functional is
 $| e |_{H^1(\Gamma)} 
   = | \nabla_\Gamma e |_{L_2(\Gamma)} 
-  = \left( \int_\Gamma | \left[\mathbf 1 - \mathbf n \otimes \mathbf
-n\right]\nabla (u-u_h) |^2 \right)^{1/2}$. This requires us to provide the
-<i>tangential</i> gradient $\left[\mathbf 1 - \mathbf n \otimes \mathbf
-n\right]\nabla u$ to the function VectorTools::integrate_difference
+  = \left( \int_\Gamma | \nabla_\Gamma (u-u_h) |^2 \right)^{1/2}$. This requires us to provide the
+<i>tangential</i> gradient to the function VectorTools::integrate_difference
 (first introduced in step-7), which we
 will do by implementing the function <code>Solution::gradient</code> in the
 program below.