1.3a Composite Function

Composite Function

If function f : X Y ,
and function g : Y Z ,
hence, composite function g f : X Z


Example:
If, f : x 2 x + 5 and g : x x 2 1 , find g f ( 2 )

Answer:
f ( x ) = 2 x + 5 f ( 2 ) = 2 ( 2 ) + 5 = 9

g f ( 2 ) = g [ f ( 2 ) ] = g ( 9 )

g ( x ) = x 2 1 g f ( 2 ) = g ( 9 ) = 9 2 1 = 80