Given $f ( x ) = \frac { 1 } { x + 2 }$

Essay

Given $f ( x ) = \frac { 1 } { x + 2 }$ and $g ( x ) = \frac { 1 } { x - 2 }$ , find $f \circ g$ , $g \circ f$ , $f \circ f$ , and $g \circ g$ , and their domains.