fix a formula error

the third formula in'update_flags.h' is fixed

diff --git a/doc/doxygen/headers/update_flags.h b/doc/doxygen/headers/update_flags.h
index d5f9e6552b6b3163618d73962cf4bb337ffe4f62..6c0caca80316f11435b5c7ae1ed3297c6cfe8d19 100644 (file)
--- a/doc/doxygen/headers/update_flags.h
+++ b/doc/doxygen/headers/update_flags.h
@@ -46,7 +46,7 @@
  * - Second, this integral is then approximated through quadrature. This yields
  *   the formula
  *   @f[
- *     A^K_{ij} = \sum_{q}J^{-1}\left[(\hat{\bf x}_q) \hat \nabla \varphi_i(\hat{\bf x}_q)\right] \cdot
+ *     A^K_{ij} = \sum_{q}\left[J^{-1}(\hat{\bf x}_q) \hat \nabla \varphi_i(\hat{\bf x}_q)\right] \cdot
  *     \left[J^{-1}(\hat{\bf x}_q) \hat \nabla \varphi_j(\hat{\bf x}_q)\right]\ |\textrm{det}\ J(\hat{\bf x}_q)|
  *     w_q,
  *   @f]