Find each of the following functions fx 1 3x gx cos xSolut
Find each of the following functions.
f(x) = 1 3x, g(x) = cos x
Solution
f(x) = 1-3x g(x) = cosx
i) f o g:
Plug x = g(X) in f(x)
So , f of = 1 - 3cosx
Domain: ( -inf , inf ) All real
ii) (g o f)(x)
Plug x = f(x) in g(x)
(g o f )(x) = cos( 1-3x)
Domain : All real ( -inf , inf)
iii) f o f
Plug x= f(x) in f(x)
f o f = 1 -3( 1-3x) = 1-3 +9x = -2 +9x
Domain : ( -inf, inf) ; All real
iv) g o g
Plug x= g(x) in g(x)
g og = cos(cos3x)
Domain: ( -inf , inf ) All real
