# Limit question

• Oct 10th 2012, 03:26 PM
funnybabe
Limit question
Hello,

I think the question is simple but not sure if this would be correct. I have a limit that is:
lim x2-25
______
x->2 sqrt (2x+6) -4

Now the bottom would be root 10 - 4, so I don't think I need to multiply it by root 10 +4 to get rid of it so is that fine?
x could not be 5

Thanks!
• Oct 10th 2012, 03:31 PM
pickslides
Re: Limit question
Correct, you dont need to multiply through by the conjugate.
• Oct 10th 2012, 03:38 PM
funnybabe
Re: Limit question
Thanks... I felt like that was a trick question or something because normally in other questions that is what you do. So you don't always have to conjugate then
• Oct 10th 2012, 04:37 PM
pickslides
Re: Limit question
No, in your case substituting the value is fine.
• Oct 10th 2012, 05:55 PM
Prove It
Re: Limit question
Quote:

Originally Posted by funnybabe
Hello,

I think the question is simple but not sure if this would be correct. I have a limit that is:
lim x2-25
______
x->2 sqrt (2x+6) -4

Now the bottom would be root 10 - 4, so I don't think I need to multiply it by root 10 +4 to get rid of it so is that fine?
x could not be 5

Thanks!

If a function is continuous at the point you are making the function approach, then the limit is equal to the function value at that point.