diff --git a/src/8_differential_equations_2.md b/src/8_differential_equations_2.md
index 33c482832a7ff25a21af2be83f6bcce8985fa537..98f09658f7e8c4ebb41655978456ee64469f21db 100644
--- a/src/8_differential_equations_2.md
+++ b/src/8_differential_equations_2.md
@@ -518,7 +518,7 @@ possible approach is to try working in a different coordinate system. There are
 a few more analytic techniques available, however in many situations it becomes
 necessary to work with numerical methods of solution. 
 
-### Problems
+## Problems
 
 1.  [:grinning:] Which of the following equations for $y(x)$ is linear?
 
@@ -571,7 +571,7 @@ necessary to work with numerical methods of solution.
 
     Which of the following operators on this space is hermitian?
 
-    (a) Lf = A(x) \frac{d^2 f}{dx^2}
+    (a) $L = A(x) \frac{d^2 f}{dx^2}$
 
-    (b) Lf = \frac{d}{dx} \big{()} A(x) \frac{df}{dx} \big{)}
+    (b) $Lf = \frac{d}{dx} \big{()} A(x) \frac{df}{dx} \big{)}$