# Thread: find limits for the functions

1. ## find limits for the functions

f(x)= x^2/x^2+x-2

lim
x--> - infinity f(x)

lim
x--> infinity f (x)

I know the answers for both are 1, however does anyone know if it is 1- or 1+?

Also, how can you tell by looking at the graph on the calculator?

2. Originally Posted by phalange
f(x)= x^2/x^2+x-2

lim
x--> - infinity f(x)

lim
x--> infinity f (x)

I know the answers for both are 1, however does anyone know if it is 1- or 1+?

Also, how can you tell by looking at the graph on the calculator?
Graph the equation on the calculator, and look for the behavior of the graph. If the graph is 1/x, for instance, it will go to 0 if x goes to positive infinity (look at the x-axis and pretend that you're going to the right of the x-axis).

When you say 1+ or 1- are you referring to positive 1 and negative 1 or "as x goes to 1 from the left or right side?"

3. If by 1+ and 1- you're asking does f approach 1 from above or below ?

1)you could solve f(x) = 1

2)note f = x^2/(x+2)(x-1) > 0 if x >1 or x < -2

if you do you get x =2 which means f crosses the horizontal asymptote at x= 2

combining 1) and 2) like Sherlock Holmes

f -> 1 from below as x - > infinity and from above as x-> -infinity