Confusing Limit Problem: Solving lim[x→-2¯(from the left)] x+2/sqrt(x^2-4)

[collinito]

Homework Statement

lim[x→-2¯(from the left)] x+2/sqrt(x^2-4)

Homework Equations

The Attempt at a Solution

When I attempted this question I felt that the solution was that this is undefined and when i put it into my ti-89 it said that too. My friend argues that it's actually zero as that's what the leftbound limit approaches graphically. I am curious now to know the answer to this one

 

[berkeman]

Homework Statement

lim[x→-2¯(from the left)] x+2/sqrt(x^2-4)

Homework Equations

The Attempt at a Solution

When I attempted this question I felt that the solution was that this is undefined and when i put it into my ti-89 it said that too. My friend argues that it's actually zero as that's what the leftbound limit approaches graphically. I am curious now to know the answer to this one

Welcome to the PF. Can you use this:

http://en.wikipedia.org/wiki/L'hospital's_rule

.

 

[collinito]

l'hospital's doesn't work, I already tried it, you still get a zero on the bottom.

 

[Mark44]

l'hospital's doesn't work, I already tried it, you still get a zero on the bottom.

Maybe you do, but I don't. Can you show us your work using L'Hopital's rule?

 

[Count Iblis]

x^2-4 = (x-2)(x+2)