revert scalar_dynam removal

HumphreyYang · HumphreyYang · commit bbd1b3913f2a · 2024-01-24T12:10:28.000+11:00
diff --git a/lectures/scalar_dynam.md b/lectures/scalar_dynam.md
@@ -515,4 +515,4 @@ and back again.
 In the current context, the series is said to exhibit **damped oscillations**.
 
 ```{solution-end}
-```
+```
