Update camera.md

docs/en/manuals/camera.md

@@ -24,7 +24,7 @@ Aspect Ratio
 : (**Perspective camera only**) - The ratio between the frustum width and height. 1.0 means that you assume a quadratic view. 1.33 is good for a 4:3 view like 1024x768. 1.78 is good for a 16:9 view. This setting is ignored if *Auto Aspect Ratio* is set.
 
 Fov
-: (**Perspective camera only**) - The *vertical* camera field of view expressed in _radians_. The wider the field of view, the more the camera will see. Note that the current default value (45) is misleading. For a 45 degree field of view, change the value to 0.785 ($\pi / 4$).
+: (**Perspective camera only**) - The *vertical* camera field of view expressed in _radians_. The wider the field of view, the more the camera will see. Note that the current default value (45) is misleading. For a 45 degree field of view, change the value to 0.785 (`π / 4`).
 
 Near Z
 : (**Perspective camera only**) - The Z-value of the near clipping plane.