rolling-eqn.html: Use `\ell' for `l' in mathematics.

It's rather clearer.

diff --git a/rolling-eqn.html b/rolling-eqn.html
index 4b5a973..c2383c4 100644 (file)
--- a/rolling-eqn.html
+++ b/rolling-eqn.html
@@ -34,10 +34,10 @@ bit, so a round wire with diameter $D$ ought to work as well as
 square wire with side $S$ if $S^2 = \pi D^2/4$, i.e.,
 \[ D = \sqrt{\frac{4 S^2}{\pi}} = \frac{2 S}{\sqrt\pi} \,\text{.} \]
 Volume is conserved, so if the original and final wire lengths
 square wire with side $S$ if $S^2 = \pi D^2/4$, i.e.,
 \[ D = \sqrt{\frac{4 S^2}{\pi}} = \frac{2 S}{\sqrt\pi} \,\text{.} \]
 Volume is conserved, so if the original and final wire lengths

-are $L$ and $l$ respectively, then
-\[ L S^2 = l w t \,\text{,} \]
+are $L$ and $\ell$ respectively, then
+\[ L S^2 = \ell w t \,\text{,} \]

 and hence
 and hence

-\[ L = \frac{l w t}{S^2} \,\text{.} \]
+\[ L = \frac{\ell w t}{S^2} \,\text{.} \]

 Finally, determining the required initial stock length $L_0$ given
 its side $S_0$ (for square stock) or diameter $D_0$ (for
 round) again makes use of conservation of volume:
 Finally, determining the required initial stock length $L_0$ given
 its side $S_0$ (for square stock) or diameter $D_0$ (for
 round) again makes use of conservation of volume: