Mathematics
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OpenStudy (anonymous):
.
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OpenStudy (solomonzelman):
I am here!
OpenStudy (solomonzelman):
@wio please ask inkyvoyd to leave!
OpenStudy (anonymous):
Yes, I have.
OpenStudy (solomonzelman):
he messed like 3 of my threads up, and distracting me after all of that!
OpenStudy (anonymous):
Okay, let me ask you a question about a limit.
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OpenStudy (solomonzelman):
Should I call a moderator, inkyvoyd?
OpenStudy (solomonzelman):
ask about the limit,, please!
OpenStudy (anonymous):
Here is a simple problem
Suppose:\[
\lim_{x\to 5}=x^2+x-9=L
\]What is \(L\)?
OpenStudy (anonymous):
Need a hint?
OpenStudy (solomonzelman):
Hold on!
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OpenStudy (solomonzelman):
Should i factor it?
OpenStudy (anonymous):
No need.
OpenStudy (solomonzelman):
yes, hint, please!
OpenStudy (anonymous):
Okay in the past I said: \[
\lim_{x\to 2}x+1=3
\]And this is because sometimes the limit the same as the actual output of the function.
OpenStudy (solomonzelman):
So i should eliminate/solve for x?
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OpenStudy (anonymous):
No. You can actually just substitute \(x=5\).
OpenStudy (solomonzelman):
why 5, how sshould i come up with substituting 5?
OpenStudy (solomonzelman):
Oh, I see b/c it is limited to 5!
OpenStudy (solomonzelman):
21?
OpenStudy (anonymous):
Let me check.
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OpenStudy (anonymous):
\[
(5)^2+(5)−9=25+5-9=21
\]Yes, that is right.
OpenStudy (anonymous):
This question was a bit unfair because I still haven't give you all the limit properties yet.
However challenging questions are good.
OpenStudy (solomonzelman):
So once you know what the limit is, it only takes an alg1 skill to solve it?
OpenStudy (anonymous):
Here is another property of limits:
Suppose that \(f(x)=x\). Then: \[
\lim_{x\to a}x = a
\]
OpenStudy (solomonzelman):
(I play chess online rating 2450)
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OpenStudy (anonymous):
Well, most limits can be solved with just algebra. There is one technique that requires derivatives. We'll get into that later.
OpenStudy (solomonzelman):
I am patios
OpenStudy (solomonzelman):
OK!
OpenStudy (solomonzelman):
Hey Rachel!
OpenStudy (anonymous):
Okay, so with the property I just showed you: \[
\lim_{x\to 100}x=L
\]What is \(L\)?
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OpenStudy (solomonzelman):
100
OpenStudy (anonymous):
Okay good.
OpenStudy (anonymous):
Oh studying! ...don't want to interrupt!
OpenStudy (anonymous):
Here is another property of limits: \[
\lim_{x\to a}x^n=a^n
\]
OpenStudy (solomonzelman):
a
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OpenStudy (solomonzelman):
it is limited to a
OpenStudy (anonymous):
What is \(L\) for:\[
\lim_{x\to 4}x^3=L
\]
OpenStudy (solomonzelman):
WOW!
OpenStudy (solomonzelman):
1?
OpenStudy (solomonzelman):
or cube root of 4
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OpenStudy (anonymous):
Nope. Remember:\[
\lim_{x\to a}x^n=a^n
\]
You need to identify \(a\) and \(n\).
OpenStudy (solomonzelman):
rachel, thank you!
OpenStudy (solomonzelman):
How?
OpenStudy (anonymous):
\[
\lim_{x\to \color{blue} 4}x^{\color{red}3}=L
\]
OpenStudy (anonymous):
\[
\lim_{x\to \color{blue}a}x^{\color{red}n}=\color{blue}a^{\color{red}n}
\]
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OpenStudy (anonymous):
I hope the color helps you see the pattern.
OpenStudy (solomonzelman):
in your 1st equation, the exponent is 3 right?
OpenStudy (anonymous):
Yes.
OpenStudy (solomonzelman):
In your last question...
OpenStudy (anonymous):
The last equation is a general formula.
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OpenStudy (solomonzelman):
I can cancel the n roots so I will have x be limited to a
and in the last, hold on need to think about that one for sec!
OpenStudy (anonymous):
The first equation is a sample problem. You use the formula to solve it
OpenStudy (solomonzelman):
the answer is 2 (for the 1st equation)
OpenStudy (anonymous):
\[
\lim_{x\to \color{blue} 4}x^{\color{red}3}=\color{blue}4^{\color{red}3}=64
\]
OpenStudy (anonymous):
My bad!
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OpenStudy (solomonzelman):
64?
OpenStudy (anonymous):
By the way, cube root \(\sqrt[3]{4}\) is close but it is like the opposite answer..
OpenStudy (solomonzelman):
the opposite?
multiplicative inverse?
OpenStudy (anonymous):
I mean the idea was close, but it was still wrong because you did opposite of what you should do.
OpenStudy (solomonzelman):
And what should I...?
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OpenStudy (anonymous):
\(\color{blue}{\text{Originally Posted by}}\) @wio
\[
\lim_{x\to \color{blue} 4}x^{\color{red}3}=\color{blue}4^{\color{red}3}=64
\]
\(\color{blue}{\text{End of Quote}}\)
OpenStudy (anonymous):
This is the correct answer.
OpenStudy (anonymous):
So you should do \(4^3\)
OpenStudy (solomonzelman):
So you do everything to a third power
OpenStudy (anonymous):
Yeah. Let us do one more problem with this property. \[
\lim_{x\to a}x^3 = 8
\]What is \(a\)?
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OpenStudy (solomonzelman):
2
OpenStudy (anonymous):
Good.
OpenStudy (solomonzelman):
TNX!
OpenStudy (solomonzelman):
Different question, if you want more medals?
OpenStudy (anonymous):
Alright.
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OpenStudy (solomonzelman):
(which you deserve!)