contestada

Which statement is true about the discontinuities of the function f(x)?
f(x)=(x^2-4)/(x^3-x^2-2x)

a. There is a hole at x = 2.
b. There are asymptotes at x = 0 and x = –1.
c. There are asymptotes at x = 0 and x = –1 and a hole at (2, 2/3)
d. There are holes at x = 0 and x = –1 and an asymptote at x = 2.

Respuesta :

In order to find out where your holes and asymptotes are is to factor both the top and the bottom of that rational function.  The numerator factors to (x+2)(x-2) and the denominator factors to x(x+1)(x-2).  So since there is an (x-2) in both the numerator and denominator, that is called a removable discontinuity which we also know as a hole.  The other factors in the denominator, the x and the (x+1) are vertical asymptotes, or values of x that make the rational function undefined (you're NEVER allowed to have a 0 in the denominator of a fraction!).  So your correct choice is c.  The way you find the y coordinate for the hole is to plug in 2 for x and solve it for y.  No biggie.

Here we need to see which statements are true about the discontinuities of the given function.

The correct option is b: "There are asymptotes at x = 0 and x = –1."

So a rational function has discontinuities when its denominator becomes equal to zero, this is because we can't divide by zero.

Here the function is:

[tex]f(x) = \frac{x^2 - 4}{x^3 - x^2 - 2x}[/tex]

First, we should factorize both numerator and denominator, so we can see if some of the factors appear in both of them and we can remove it.

For the numerator we have:

[tex]x^2 - 4 = x^2 - 2^2 = (x + 2)*(x - 2)[/tex]

For the denominator we have:

[tex]x^3 - x^2 - 2x = x*(x^2 - x - 2)[/tex]

Now we need to find the factorization of the thing inside the parenthesis.

The roots are given by Bhaskara's formula:

[tex]x = \frac{-(-1) \pm \sqrt{(-1)^2 - 4*1*(-2)} }{2*1} \\\\x = \frac{1 \pm 3 }{2}[/tex]

So the roots are:

x = (1 + 3)/2 = 2

x = (1 - 3)/2 = -1

And we can rewrite:

[tex]x^3 - x^2 - 2x = x*(x^2 - x - 2) = x*(x + 1)*(x - 2)[/tex]

Then the function can be rewritten as:

[tex]f(x) = \frac{x^2 - 4}{x^3 - x^2 - 2x} = \frac{(x + 2)*(x - 2)}{x*(x + 1)*(x - 2)} = \frac{x + 2}{x*(x + 1)}[/tex]

Then the discontinuities are at the zeros of the denominator, which are at x = 0 and x = -1.

Because the denominator goes to zero at these points, we will have vertical asymptotes, thus the correct option is b

"There are asymptotes at x = 0 and x = –1."

If you want to learn more, you can read:

https://brainly.com/question/17317969