Answer :
Given f(x) = 2x + 3 and g(x) = –x2 + 5, find ( f o f )(x).( f o f )(x) = f ( f (x))
= f (2x + 3)
= 2( ) + 3 ... setting up to insert the input
= 2(2x + 3) + 3
= 4x + 6 + 3
= 4x + 9Given f(x) = 2x + 3 and g(x) = –x2 + 5, find (g o g)(x).(g o g)(x) = g(g(x))
= –( )2 + 5 ... setting up to insert the input
= –(–x2 + 5)2 + 5
= –(x4 – 10x2 + 25) + 5
= –x4 + 10x2 – 25 + 5
= –x4 + 10x2 – 20
= f (2x + 3)
= 2( ) + 3 ... setting up to insert the input
= 2(2x + 3) + 3
= 4x + 6 + 3
= 4x + 9Given f(x) = 2x + 3 and g(x) = –x2 + 5, find (g o g)(x).(g o g)(x) = g(g(x))
= –( )2 + 5 ... setting up to insert the input
= –(–x2 + 5)2 + 5
= –(x4 – 10x2 + 25) + 5
= –x4 + 10x2 – 25 + 5
= –x4 + 10x2 – 20
Sometimes you have to be careful with the domain and range of the composite function.
Given f (x) = sqrt(x) and g(x) = x – 2, find the domains of ( f o g)(x) and (g o f )(x).