HEEELP

let f(x) =1/x-3 and g(x)=√x+5. What is the domain of (f o g)(x)

Options

a) [-5,-4)U(-4, inf)

b) [-5,-3)U(-3,inf)

c)[-f,4)U(4,inf)

d)[-5,3)U(3,inf)

Answer :

Answer: (c)

Step-by-step explanation:

Given

[tex]f(x)=\dfrac{1}{x-3}\\\\g(x)=\sqrt{x+5}[/tex]

Here, [tex]\sqrt{x+5}\ \text{is always greater than equal to 0}\\\Rightarrow x+5\geq 0\\\Rightarrow x\geq -5\quad \ldots(i)[/tex]

To get [tex]f\left(g(x)\right)[/tex], replace [tex]x[/tex] in [tex]f(x)[/tex] by [tex]g(x)\ \text{i.e. by}\ \sqrt{x+5}[/tex]

[tex]\Rightarrow f\left(g(x)\right)=\dfrac{1}{\sqrt{x+5}-3}\\\\\text{Denominator must not be equal to 0}\\\\\therefore \sqrt{x+5}-3\neq0\\\Rightarrow \sqrt{x+5}\neq 3\\\Rightarrow x+5\neq 9\\\Rightarrow x\neq 4\quad \ldots(ii)[/tex]

Using [tex](i)[/tex] and [tex](ii)[/tex]  it can be concluded that the domain of [tex]f\left(g(x)\right)[/tex] is all real numbers except 0.

Therefore, its domain is given by

[tex]x\in [-5,4)\cup (4,\infty)[/tex]

Option (c) is correct.

Answer:

its d

Step-by-step explanation:

i did the iready diagnostic test. :)

Other Questions