Step-by-step explanation:
Vertical asymptote can be Identites if there is a factor only in the denominator. This means that the function will be infinitely discounted at that point.
For example,
![\frac{1}{x - 5}](https://tex.z-dn.net/?f=%20%5Cfrac%7B1%7D%7Bx%20-%205%7D%20)
Set the expression in the denominator equal to 0, because you can't divide by 0.
![x - 5 = 0](https://tex.z-dn.net/?f=x%20-%205%20%3D%200)
![x = 5](https://tex.z-dn.net/?f=x%20%3D%205)
So the vertical asymptote is x=5.
Disclaimer if you see something like this
![\frac{(x - 5)(x + 3)}{(x - 5)}](https://tex.z-dn.net/?f=%20%5Cfrac%7B%28x%20-%205%29%28x%20%2B%203%29%7D%7B%28x%20-%205%29%7D%20)
x=5 won't be a vertical asymptote, it will be a hole because it in the numerator and denominator.
Horizontal:
If we have a function like this
![\frac{1}{x}](https://tex.z-dn.net/?f=%20%5Cfrac%7B1%7D%7Bx%7D%20)
We can determine what happens to the y values as x gets bigger, as x gets bigger, we will get smaller answers for y values. The y values will get closer to 0 but never reach it.
Remember a constant can be represent by
![a \times {x}^{0}](https://tex.z-dn.net/?f=a%20%5Ctimes%20%20%7Bx%7D%5E%7B0%7D%20)
For example,
![1 = 1 \times {x}^{0}](https://tex.z-dn.net/?f=1%20%3D%201%20%5Ctimes%20%20%7Bx%7D%5E%7B0%7D%20)
![2 = 2 \times {x}^{0}](https://tex.z-dn.net/?f=2%20%3D%20%202%20%5Ctimes%20%7Bx%7D%5E%7B0%7D%20)
And so on,
and
![x = {x}^{1}](https://tex.z-dn.net/?f=x%20%3D%20%20%7Bx%7D%5E%7B1%7D%20)
So our equation is basically
![\frac{1 \times {x}^{0} }{ {x}^{1} }](https://tex.z-dn.net/?f=%20%5Cfrac%7B1%20%5Ctimes%20%20%7Bx%7D%5E%7B0%7D%20%7D%7B%20%7Bx%7D%5E%7B1%7D%20%7D%20)
Look at the degrees, since the numerator has a smaller degree than the denominator, the denominator will grow larger than the numerator as x gets larger, so since the larger number is the denominator, our y values will approach 0.
So anytime, the degree of the numerator < denominator, the horizontal asymptote is x=0.
Consider the function
![\frac{3 {x}^{2} }{ {x}^{2} + 1}](https://tex.z-dn.net/?f=%20%5Cfrac%7B3%20%7Bx%7D%5E%7B2%7D%20%7D%7B%20%7Bx%7D%5E%7B2%7D%20%20%2B%201%7D%20)
As x get larger, the only thing that will matter will be the leading coefficient of the leading degree term. So as x approach infinity and negative infinity, the horizontal asymptote will the numerator of the leading coefficient/ the leading coefficient of the denominator
So in this case,
![x = \frac{3}{1}](https://tex.z-dn.net/?f=x%20%3D%20%20%5Cfrac%7B3%7D%7B1%7D%20)
Finally, if the numerator has a greater degree than denominator, the value of horizontal asymptote will be larger and larger such there would be no horizontal asymptote instead of a oblique asymptote.