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Mathematics 20 Online
OpenStudy (anonymous):

Can someone help me on this problem..? It is attached.

OpenStudy (anonymous):

OpenStudy (anonymous):

if you show me how to find it, I'll do it on my own. I'm not expecting answers for this huge problem.

OpenStudy (anonymous):

Just follow the graph lines. So like: \[\lim_{x \rightarrow 2^{-}}\] You would simply trace your finger along the curve starting on the left hand side until you get to 2. Whatever y-value it's approaching at the point x=2, that's your answer :)

OpenStudy (anonymous):

as g approaches 0 from the left, and also from the right, the function is approaching some number a little larger than 3, the \(y\) value

OpenStudy (anonymous):

So as x approaches 2- ... its 3?

OpenStudy (anonymous):

as @nj1202 said. and if you are approaching 2 from the right, that is for \(\lim_{x\to 0^+}\) trace your finger on the curve going from right to left and see what \(y\) value you are approaching

OpenStudy (anonymous):

yes

OpenStudy (anonymous):

2 from the right= 1?

OpenStudy (anonymous):

yes only tricky one is \[\lim_{x\to 2}\]

OpenStudy (anonymous):

The limit doesn't exist?

OpenStudy (anonymous):

and since the above answers are not the same (that is \(3\neq 2\)) then that limit does not exist yes

OpenStudy (anonymous):

So it's no number, its just the the DNE.

OpenStudy (anonymous):

limit*

OpenStudy (anonymous):

yes

OpenStudy (anonymous):

what about g(2)? that's different.

OpenStudy (anonymous):

Just a helpful hint for when these are loaded into a test. NEVER!! EVER!! write that the limit DNE for a one-sided limit. Only when it's approaching from both sides can you say DNE.

OpenStudy (anonymous):

g(2) means x=2, so just find that point.

OpenStudy (anonymous):

which point do I go to though?

OpenStudy (anonymous):

for x=2 theres two?

OpenStudy (anonymous):

Yes, but notice how one is shaded and the other is a circle. The circle means that the point is not defined at that x value. The shaded means that it is. It's called a jump in a function. g(2) = 3

OpenStudy (anonymous):

why is it 3 (shaded) and not 1(unshaded)?

OpenStudy (anonymous):

Because the shading refers to where the point is actually defined. Think of when you draw a graph. If you were to simply plot a point on a cartesian plane, what would you do? You'd shade a small circle onto the graph and write the coordinates. The reason it's not 1 is because it's unshaded. Unshaded means that the x-value is not included in the domain of the function.

OpenStudy (anonymous):

ohh.. okay. So for any number to be in g(?)... it has to be included. its never an unshaded point.

OpenStudy (anonymous):

Also, is as the limit approaches 4 g(t)=4?

OpenStudy (anonymous):

Actually i can't see the picture, is that another unshaded circle? at x=4?

OpenStudy (anonymous):

and its continuous because of the jump continuity?

OpenStudy (anonymous):

Well, usually we just say jump discontinuity if it's not continuous. So it's just continuous. The thing is I missed x=4 and there looks like an unshaded circle, so it's undefined, and not continuous like i thought it was xD

OpenStudy (anonymous):

when I look at x=4 and follow it up to y there is an unshaded circle at (4,4)

OpenStudy (anonymous):

Ok, I couldn't tell in the photo. So yea, the limit still exists though, because regardless of if you approach x=4 from the left or from the right, you approach y=4, so since they are the same, it exists even at a point of being undefined. Tricky question :)

OpenStudy (anonymous):

so... as the limit approaches 4, g(t) is undefined.

OpenStudy (anonymous):

im a lil confused now haha..

OpenStudy (anonymous):

haha i'm sorry xD i'll get this through to you! :D okay, so the point g(4) is undefined, because it is unshaded. however, look at both one-sided limits of x=4. x=4 from the left, you approach y=4 x=4 from the right, you approach y=4 since the two one-sided limits are the same, the limit exists

OpenStudy (anonymous):

okay, so g(4) is undefined. However as x approaches 4- its 4 and 4+ its 4. the limit of g(4) exists making g(4)=4 ? is that right?

OpenStudy (anonymous):

Well, no g(4) does not = 4, the limit as x-->4 is 4.

OpenStudy (anonymous):

g(4) is undefined. then But, As x approaches the limit of 4, g(x)=4?

OpenStudy (anonymous):

Yup. That's it!

OpenStudy (anonymous):

holy crap. time for a nap. haha

OpenStudy (anonymous):

haha wish i could say the same, i got calc III at 5pm xD

OpenStudy (anonymous):

aww, :/ one more question and i'll try to understand faster.. lol!

OpenStudy (anonymous):

no problem. my walk is 5 minutes. what's up? :D

OpenStudy (anonymous):

The question is wanting me to find the limit as x approaches 0 from both sides... but when I go to x=0 the y is only a little bit above the three mark.. and no shaded circle or unshaded?

OpenStudy (anonymous):

Yea, i saw that. You would just put the limit is approaching a little more than 3. I don't know how you'd write that haha xD It's like 3.1 or 3.2 i guess xD but the same rule should apply to it.

OpenStudy (anonymous):

So for 0- would it be g(x)=3.1? like that...?

OpenStudy (anonymous):

Yea that shoud be fine, that is what it's approaching.

OpenStudy (anonymous):

I don't know why the people would be mean and ask for something just randomly off a line, but oh well xD

OpenStudy (anonymous):

and is it the same for 0+?

OpenStudy (anonymous):

haha yeah well, my professor... uhm, I can't understand her. (Chinese) :/ so I have to learn everything on my own....

OpenStudy (anonymous):

yup exactly the same! oo, accents are hard sometimes haha xD

OpenStudy (anonymous):

and as x approaches 0 g(t)= 3.1 as well and the limit exists?

OpenStudy (anonymous):

It certainly does! :D

OpenStudy (anonymous):

and yes, it sucks!

OpenStudy (anonymous):

haha my only foreign teacher this semester is my EM theory xD he's german, so it's quite gutteral xD

OpenStudy (anonymous):

my goodness, thank you so much! I wish I could like take you to lunch or something instead of giving you a best response lol.. I have quite a few:/ I guess that's what you get for being in engineering.

OpenStudy (anonymous):

Haha I'm astronomy/astrophysics so i'm in the math business too. I'm usually one quite a bit, just shoot me a question :D

OpenStudy (anonymous):

I was going to do astrophysics! but decided on Aerospace Engineering (Astronautics). and okay will do!

OpenStudy (anonymous):

Sweet deal buddy :D Space geeks will rule the world! Don't let anyone tell ya otherwise haha xD

OpenStudy (anonymous):

hahaha agreed! talk to you later :) thanks so much again!

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