# Math Help - finding limits

1. ## finding limits

if f(x)={2-x, x<-1
x, -1<=x<1
(x-1)^2, x>=1}

find limit (f(x), x, -1-)
limit (f(x), x, -1+)

I have graphed the functions above but do not know how to find the limits, can someone please explain the steps needed?

Thanks!

2. $\underset{x\to -1^{-}}{\mathop{\lim }}\,(2-x)$ and $\underset{x\to -1^{+}}{\mathop{\lim }}\,x,$ got it?

3. No, because I don't even know how to start finding limits. I have seen them written this way, but I don't know what it means. I don't care if you solve my particular problem, but if you could just show me some kind of example I could follow, it would be very helpful!

4. Originally Posted by sjenkins
No, because I don't even know how to start finding limits. I have seen them written this way, but I don't know what it means. I don't care if you solve my particular problem, but if you could just show me some kind of example I could follow, it would be very helpful!
$\lim_{x \to -1^-} \cdots$ means "the limit as x tends to -1 from the left of ..."

$\lim_{x \to -1^+} \cdots$ means "the limit as x tends to -1 from the right of ..."

so when it asks $\lim_{x \to -1^-}f(x)$, you say, okay, i am coming from the left of -1, that means, i want the function as it is defined for x < -1, because those are the values to the left of -1. now i look at my function and realize that for x < -1, the function is 2 - x

so i want $\lim_{x \to -1^-} (2 - x)$

this function is continuous, so you can just plug in -1 to find the limit.

$\lim_{x \to -1^-} (2 - x) = 2 - (-1) = 3$

a similar story holds true for the other one-sided limit

5. Thank you, I can finally understand that. I really appreciate the help!