How do you graph f(x)=(2x^2)/(x-3) using holes, vertical and horizontal asymptotes, x and y intercepts?

1 Answer
Jan 18, 2018

Let's find the holes of this formula. A hole means that the same factor is in the numerator as denominator and they divide out. Such as (x^2)/(x^3-4x) or (cancel(x) xx x)/(cancel(x)(x^2-4) so there is a hole when x = 0.

In our case of (2x^2)/(x-3), there are no common factors, so there is no hole.

Vertical asymptotes occur when we try to divide a value by 0. So let's see what value of x makes the denominator equal to 0:

x-3=0

x=3

So, there is a vertical asymptote at x = 3

Now let's see about the Horizontal asymptote.

I like to use this to help me remember:

BOBO - Bigger on bottom, y=0

BOTN - Bigger on top, none

EATS DC - Exponents are the same, divide coefficients

So in our case, the numerator (top) has a greater exponent (bigger). So there is no Horizontal asmptote (BOTN)

Now let's find the x- intercepts and y- intercepts:

x-intercept is the value of x when y equals 0:

0 = (2x^2)/(x-3)

0 = 2x^2

0 = x^2

x = 0

The y-intercept is the value of y when x equals 0

y = (2(0)^2)/(0-3)

y = 0/-3

y = 0

Now we have all the information we need

To check our answers, let's graph the equation
graph{y=(2x^2)/(x-3)}

We have an x and y intercept at 0, that's right. There's no horizontal asymptote although there is an asymptote for x = 3

Our math is correct. Good job