Update 705-math-absmax.markdown

Author: Joe7M

_build/reference/705-math-absmax.markdown

@@ -4,4 +4,17 @@
 
 Returns the absolute max value of x.
 
+```
+' absmax of three values
+print absmax(-3,-1,2)
 
+' absmax of three variables
+a = -3
+b = -1
+c =  2
+print absmax(a,b,c)
+
+' absmax of an array
+a = [-3,-1,2]
+print absmax(a)
+```