# Thread: Help with limits

1. ## Help with limits

Hi im new to this site and i havent had a math class in a year. I just attended my economics math class and i wanted to ask a question about limits. I have no clue what this is and i have stared at it for at least an hour. The problem says use the graph of the function of f shown below to estimate the indicated limits and function values? Obviously i can not show you the graph. Is there any where on the web or any advice that you can shoot my way. The first problem looks like this lim f(x)
x-0_
let me explain the minus sign is an arrow and the underscore actually is an over score. If that makes since. Please help i know i didnt give you a great explaination but i will be by my computer for the rest of the day. Please help.
thanks,
jpehl

2. What is the function they gave you? What's f(x)?

3. hmmmm dont see a function what was given is a graph and a problem that is
lim F(X)
x (arrow)o_

4. Maybe if you just try explaining limits to me it might better help me understand.
jpehl

5. Originally Posted by jpehl
hmmmm dont see a function what was given is a graph and a problem that is
lim F(X)
x (arrow)o_
I assume what you have is: $\lim_{x \to 0^-}f(x)$?

The trouble is we can't really help out much unless we can see the graph or have an expression for the function. What I CAN say is that you are looking for what the function f(x) tends to (approaches) as x approaches the value 0 from the negative side (left side) of 0. The function value may or may not exist at x = 0, but the function may well approach a value.

For example, $\frac{(x+5)(x-5)}{x-5}$ does not exist at the point x = 5, but as we get very very close to x = 5 this expression gets very very close to 5 + 5 = 10. (Try a value of x = 4.99999 in your calculator.)

Another possibility is that the limit of your function may not exist for an infinitesimally small negative x value. This would be the case if the absolute value of the function blows up (goes to infinity) at x = 0.

Without more information, that's the best I can do for you.

-Dan

6. okay that helps tell me how you posted the formula. Maybe next time i will not have to write crazy things out.
jpehl

7. Is it possible that you can give me an example with a graph or is that not possible. jpehl

8. Originally Posted by jpehl
Is it possible that you can give me an example with a graph or is that not possible. jpehl
I can't post graphs because I don't currently have a (working) scanner. There is a tutorial on posting LaTeX here: http://www.mathhelpforum.com/math-he...read.php?t=266

I've also found the following link helpful for other commands:
http://meta.wikimedia.org/wiki/Help:Formula

-Dan

9. okay let me try this formula out also if you could reply back with a detailed answer explaining how you got the answer.
$\lim_{x\to3}4x$

jpehl

10. Originally Posted by jpehl
Hi im new to this site and i havent had a math class in a year. I just attended my economics math class and i wanted to ask a question about limits. I have no clue what this is and i have stared at it for at least an hour. The problem says use the graph of the function of f shown below to estimate the indicated limits and function values? Obviously i can not show you the graph. Is there any where on the web or any advice that you can shoot my way. The first problem looks like this lim f(x)
x-0_
let me explain the minus sign is an arrow and the underscore actually is an over score. If that makes since. Please help i know i didnt give you a great explaination but i will be by my computer for the rest of the day. Please help.
thanks,
jpehl
Your first stops with this sort of question should always be GOOGLE, WIKIPEDIA and MATHWORLD.

In this case one of the top hits from google is this which looks quite good.

RonL

11. Do not beg!!!
You can wait.
--=USER WARNED=--

12. You can find a good lesson on limits in Quicklopedia

(I've been too lazy to figure out what I did wrong, so don't expect Quicklopedia to get an update on it anytime soon)

just look at the graph and come up with a table in your mind...

13. Thanks quick i will check it out. For hacker im new and i was not begging at all. I simpily wanted to understand my homework. Moderator or not your on a power trip. I was making sure that it was not skipped over. So please im not here to bother anyone I just want to learn. If theres a problem address me personally do not call me out again. If this is a problem i shall go else where.
jpehl

14. Originally Posted by jpehl
If theres a problem address me personally do not call me out again.
1)I was demonstrating my power. If you were Godlike would you not use it?

2)I am evil. I am ammused by turtore. I was designed evil. My idol, Eric Cartman is also evil.

3)Taking someone inside (privately) to scream at them is a Picard (CaptainBlank) thing to do. A Kirk thing is to scream at them in public.

4)Then why is it that you did not PM me if you were accusing me and according to you people should not accuse in public?

5)Can someone really be shamed through the interent?
---
Conclusion,
You must be female.

15. Originally Posted by jpehl
I have bad news you have no power. The good news im not going to argue with a child. Have a nice evening . jpehl
Assuming you are still around, did you look at the links provided? They seem to be pretty good explanations to me.

-Dan

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