Update examples/step-68/doc/intro.dox

Co-authored-by: Peter Munch <peterrmuench@gmail.com>

diff --git a/examples/step-68/doc/intro.dox b/examples/step-68/doc/intro.dox
index 9314c3782a8882c50178c8607dab98f89adecfd4..9619be6cf08c6dc2b9f1474314c30a66a7a2f1d5 100644 (file)
--- a/examples/step-68/doc/intro.dox
+++ b/examples/step-68/doc/intro.dox
@@ -45,7 +45,7 @@ where $\textbf{x}_{i}^{t+\Delta t}$ and $\textbf{x}_{i}^{t}$ are the position
 of particle $i$ at time $t+\Delta t$ and $t$, respectively and where $\Delta t$
 is the time step. In the present step, the velocity at the location of particles
 is obtainedin two different fashions:
-- By evaluating the velocity function at the location of the particles
+- By evaluating the velocity function at the location of the particles.
 - By evaluating the velocity function on a background triangulation and, using
 a  finite element support, interpolating at the position of the particle.