Use the functions f(x) =x^ 2 -3 and g(x) = 2x- 1. Find each of the following, What is (f+g) (2) ? What is (f/g) (-1) What is the domain of (f.g)(x)

Respuesta :

Solution:

Given the functions

[tex]\begin{gathered} f(x)=x^2-3 \\ g(x)=2x-1 \end{gathered}[/tex]

PART 1:

Concept:

[tex](f+g)(x)=f(x)+g(x)[/tex]

By applying the rule above, we will have

[tex]\begin{gathered} (f+g)(x)=f(x)+g(x) \\ (f+g)(x)=x^2-3+2x-1 \\ (f+g)(x)=x^2+2x-3-1 \\ (f+g)(x)=x^2+2x-4 \end{gathered}[/tex]

To figure out (f+g)(2) means that we are going to substitute the value of x as 2

[tex]\begin{gathered} (f+g)(x)=x^2+2x-4 \\ (f+g)(2)=2^2+2(2)-4 \\ (f+g)(2)=4+4-4 \\ (f+g)(2)=4 \end{gathered}[/tex]

Hence,

(f+g)(2) = 4

PART 2:

Concept:

[tex](\frac{f}{g})(x)=\frac{f(x)}{g(x)}[/tex]

By applying the rule above, we will have

[tex]\begin{gathered} (\frac{f}{g})(x)=\frac{f(x)}{g(x)} \\ (\frac{f}{g})(x)=\frac{x^2-3}{2x-1} \end{gathered}[/tex]

To figure out the value of (f/g)(-1) means we will substitute the value of x=-1

[tex]\begin{gathered} (\frac{f}{g})(x)=\frac{x^2-3}{2x-1} \\ (\frac{f}{g})(-1)=\frac{(-1)^2-3}{2(-1)-1} \\ (\frac{f}{g})(-1)=\frac{1-3}{-2-1} \\ (\frac{f}{g})(-1)=\frac{-2}{-3} \\ (\frac{f}{g})(-1)=\frac{2}{3} \end{gathered}[/tex]

Hence,

(f/g)(-1) = 2/3

PART 3:

To figure out the domain of (f.g)(x)

[tex](f.g)(x)=f(x)\text{.g(x)}[/tex]

By applying the formula above, we will have

[tex]\begin{gathered} (f.g)(x)=f(x)\text{.g(x)} \\ (f.g)(x)=(x^2-3)(2x-1) \\ (f.g)(x)=x^2(2x-1)-3(2x-1) \\ (f.g)(x)=x^3-x^2-6x+3 \end{gathered}[/tex]

Hence,

The domain of the above set of equations is given below as

[tex]=\quad \begin{bmatrix}\mathrm{Solution\colon}\: & \: -\infty\: