Rewrite "Lagrange multiplier", various improvements

1 files changed, 2 insertions, 2 deletions

diff --git a/source/know/concept/material-derivative/index.md b/source/know/concept/material-derivative/index.md
index 93e8ad0..7225053 100644
--- a/source/know/concept/material-derivative/index.md
+++ b/source/know/concept/material-derivative/index.md
@@ -16,9 +16,9 @@ e.g. the temperature or pressure,
 represented by a scalar field $$f(\va{r}, t)$$.
 
 If the fluid is static, the evolution of $$f$$ is simply $$\ipdv{f}{t}$$,
-since each point of the fluid is motionless.
+since each point is motionless.
 However, if the fluid is moving, we have a problem:
-the fluid molecules at position $$\va{r} = \va{r}_0$$ are not necessarily
+the fluid molecules at position $$\va{r} = \va{r}_0$$ are not
 the same ones at time $$t = t_0$$ and $$t = t_1$$.
 Those molecules take $$f$$ with them as they move,
 so we need to account for this transport somehow.