Update test.md

docs/test.md

 # Test markdown documentation
 
-Here is a mermaid graph
+
+## MathJax Test
+
+When $a \ne 0$, there are two solutions to \(ax^2 + bx + c = 0\) and they are
+$$x = {-b \pm \sqrt{b^2-4ac} \over 2a}.$$
+
+
+
+## Here is a mermaid graph
 
 ```mermaid
 sequenceDiagram
@@ -15,7 +23,7 @@ sequenceDiagram
 	end
 ```
 
-and here is a note
+## and here is a note
 
 .. note::