fix?

sin x = 2.md

@@ -19,7 +19,7 @@ $$
 u - u^{-1} = 4i
 $$
 $$
-u^2 - 1 = 4iu $$
+u^2 - 1 = 4iu
 $$
 u^2 - 4iu - 1 = 0
 $$
@@ -27,13 +27,13 @@ $$
 u^2 - 4iu - 4 = -3
 $$
 $$
-(u - 2i)^2 = -3 \\
+(u - 2i)^2 = -3
 $$
 $$
 u - 2i = \pm \sqrt {-3} 
 $$
 $$
-u = 2i \pm \sqrt {-3} \\
+u = 2i \pm \sqrt {-3}
 $$
 $$
 u = i(2 \pm \sqrt 3)