updates

doc/pub/tutorial/._pysketcher003.html

@@ -773,7 +773,8 @@ $$ \frac{|\half C_D\varrho \pi R^2 |v|v|}{|mg|}\sim
 \sim \frac{C_D\varrho \pi R^2 L}{2m}\theta_0^2 = \alpha \theta_0^2\tp$$
 
 (We have that \( \theta(t)/d\theta_0 \) is in \( [-1,1] \), so we expect
-since \( \theta_0^{-1}d\bar\theta/d\bar t \) to be around unity.)
+since \( \theta_0^{-1}d\bar\theta/d\bar t \) to be around unity. Here,
+\( \theta_0=\theta(0) \).)
 
 <p>
 The next step is to write a numerical solver for

doc/pub/tutorial/html/_sources/main_sketcher.txt

@@ -1230,7 +1230,8 @@ the ratio of the drag force and the gravity force:
         \sim \frac{C_D\varrho \pi R^2 L}{2m}\theta_0^2 = \alpha \theta_0^2{\thinspace .}
 
 (We have that :math:`\theta(t)/d\theta_0` is in :math:`[-1,1]`, so we expect
-since :math:`\theta_0^{-1}d\bar\theta/d\bar t` to be around unity.)
+since :math:`\theta_0^{-1}d\bar\theta/d\bar t` to be around unity. Here,
+:math:`\theta_0=\theta(0)`.)
 
 The next step is to write a numerical solver for
 :eq:`sketcher:ex:pendulum:anim:eq:ith:s`-:eq:`sketcher:ex:pendulum:anim:eq:ir:s`. To

doc/pub/tutorial/html/main_sketcher.html

@@ -1038,7 +1038,8 @@ the ratio of the drag force and the gravity force:</p>
 \left|\frac{d\bar\theta}{d\bar t}\right|\frac{d\bar\theta}{d\bar t}
 \sim \frac{C_D\varrho \pi R^2 L}{2m}\theta_0^2 = \alpha \theta_0^2{\thinspace .}\]</div>
 <p>(We have that <span class="math">\(\theta(t)/d\theta_0\)</span> is in <span class="math">\([-1,1]\)</span>, so we expect
-since <span class="math">\(\theta_0^{-1}d\bar\theta/d\bar t\)</span> to be around unity.)</p>
+since <span class="math">\(\theta_0^{-1}d\bar\theta/d\bar t\)</span> to be around unity. Here,
+<span class="math">\(\theta_0=\theta(0)\)</span>.)</p>
 <p>The next step is to write a numerical solver for
 <a href="#equation-sketcher:ex:pendulum:anim:eq:ith:s">(3)</a>-<a href="#equation-sketcher:ex:pendulum:anim:eq:ir:s">(4)</a>. To
 this end, we use the <a class="reference external" href="https://github.com/hplgit/odespy">Odespy</a>