If f(x)=2x and g(x)=x^2 -1, which statement is true?

A. (f • g) (x) = 2x^2 - 1
B. (f • g) (x) = 2x(x^2-1)
C. (g • f) (x) = 4x - 1
D. (g • f) (x) = 4x^2 -1

Respuesta :

Answer: D

Step-by-step explanation:

f(x) = 2x     g(x) = x² - 1

f(g(x)) = 2(x² - 1)

         = 2x² - 2

g(f(x)) = (2x)² - 1

         = 4x² - 1

Using composite function concepts, it is found that the correct statement is:

D. [tex](g \circ f)(x) = 4x^2 - 1[/tex]

The composite function definition is given by:

[tex](f \circ g)(x) = f(g(x))[/tex]

[tex](g \circ f)(x) = g(f(x))[/tex]

In this problem:

[tex]f(x) = 2x[/tex]

[tex]g(x) = x^2 - 1[/tex]

Then

[tex](f \circ g)(x) = f(x^2 - 1) = 2(x^2 - 1) = 2x^2 - 2[/tex]

[tex](g \circ f)(x) = g(2x) = (2x)^2 - 1 = 4x^2 - 1[/tex]

Then, the correct statement is:

D. [tex](g \circ f)(x) = 4x^2 - 1[/tex]

A similar problem is given at https://brainly.com/question/9484507