Calculus Help for College Newbie: Limit to Infinity

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Homework Help Overview

The discussion revolves around understanding limits in calculus, specifically related to expressions involving square roots and limits approaching infinity. Participants are exploring the manipulation of algebraic expressions to evaluate limits.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss rewriting expressions to facilitate limit evaluation, such as transforming \(\frac{\sqrt{4-x^2}}{x-2}\) into a different form. Questions arise about the validity of these transformations and how to handle indeterminate forms like \(\frac{0}{0}\).

Discussion Status

Some participants are actively seeking clarification on the steps involved in rewriting the expressions. There is acknowledgment of the need for further breakdown of the concepts, particularly regarding the manipulation of limits and the implications of certain algebraic forms. Guidance has been offered regarding factor cancellation, but consensus on the approach has not been reached.

Contextual Notes

Participants have noted the complexity of the questions and the challenges of expressing them in text format, leading to reliance on images. There is also mention of forum rules regarding demonstrating prior attempts at solving the problems.

kuskus94
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Hi, I am a newbie here and a newbie too at calculus since I just started my first year in college. Anyway, there are some questions that I don't quite understand and I hope that anyone can help me with this.

http://sphotos-a.ak.fbcdn.net/hphotos-ak-ash4/269471_368130629940171_945927165_n.jpg

I am sorry for the use of an image because I think that the questions are quite complex for me to write on keyboard.

Thank you in advance. :)
 
Last edited by a moderator:
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a) write
\frac{\sqrt{4-x^2}}{x-2}=\sqrt{-1+\frac{4}{x-2}}
b) use the fact
e=\lim_{x \rightarrow \infty} \left( 1+\frac{1}{n} \right) ^n
 
Last edited:
kuskus94 said:
Hi, I am a newbie here and a newbie too at calculus since I just started my first year in college. Anyway, there are some questions that I don't quite understand and I hope that anyone can help me with this.

http://sphotos-a.ak.fbcdn.net/hphotos-ak-ash4/269471_368130629940171_945927165_n.jpg

I am sorry for the use of an image because I think that the questions are quite complex for me to write on keyboard.

Thank you in advance. :)
Hello kuskus94. Welcome to PF !

\displaystyle \frac{\sqrt{x^2-4}}{x-2}=\frac{\sqrt{(x-2)(x+2)}}{x-2}
 
Last edited by a moderator:
lurflurf said:
a) write
\frac{\sqrt{4-x^2}}{x-2}=\sqrt{-1+\frac{4}{x-2}}
b) use the fact
e=\lim_{x \rightarrow \infty} \left( 1+\frac{1}{n} \right) ^n

Dear lurflurf,

I sill don't get how the question a) can me modified to be like that and I would like to ask you to break it down more for me.

As for question b), I apologize that my lack of reading. It is my bad to not read the calculus book deeper. :blushing:

Thank you for your reply.

SammyS said:
Hello kuskus94. Welcome to PF !

\displaystyle \frac{\sqrt{x^2-4}}{x-2}=\frac{\sqrt{(x-2)(x+2)}}{x-2}

Dear SammyS,

I thank you for welcoming me in this forum. But then I got a waring message from Mark44 (the admin to my suppose) beacuse I didn't state that I have tried doing this question. Well, it was my bad :-p.

For the question a), I still got {\sqrt{0}} over 0. I don't think I have any other idea to workaround this question. I would be really glad if you can help me more. :biggrin:

Thank you in advance.
 
kuskus94 said:
...

Dear SammyS,

I thank you for welcoming me in this forum. But then I got a waring message from Mark44 (the admin to my suppose) because I didn't state that I have tried doing this question. Well, it was my bad :-p.

For the question a), I still got {\sqrt{0}} over 0. I don't think I have any other idea to workaround this question. I would be really glad if you can help me more. :biggrin:

Thank you in advance.
You can cancel one of the factors in the numerator. What is \displaystyle \frac{\sqrt{u}}{u}\ or \displaystyle \frac{\sqrt{3}}{3}\ ?
 
SammyS said:
You can cancel one of the factors in the numerator. What is \displaystyle \frac{\sqrt{u}}{u}\ or \displaystyle \frac{\sqrt{3}}{3}\ ?

Ah, I see... Thank you very much for your help. :)
 

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