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cwrw238
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I continue to have trouble solving limits in calculus. Can anybody recommend a good website which deals with this. An 'idiots guide' ?
 2 years ago
 2 years ago
cwrw238 Group Title
I continue to have trouble solving limits in calculus. Can anybody recommend a good website which deals with this. An 'idiots guide' ?
 2 years ago
 2 years ago

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ParthKohli Group TitleBest ResponseYou've already chosen the best response.1
1) People who are not idiots don't need an idiots' guide. 2) http://tutorial.math.lamar.edu/
 2 years ago

cwrw238 Group TitleBest ResponseYou've already chosen the best response.0
lol  thank you parthkohli  i'll take a look
 2 years ago

agentc0re Group TitleBest ResponseYou've already chosen the best response.1
You're not an idiot. Limits are tricky business. What kind of limits are you having trouble with? Limits approaching infinity? Zero? or some other finite #?
 2 years ago

cwrw238 Group TitleBest ResponseYou've already chosen the best response.0
i think limits approaching 0 and infinity
 2 years ago

agentc0re Group TitleBest ResponseYou've already chosen the best response.1
Limits approaching infinity have 3 "rules" to make this a bit more simple. \[\lim_{x \rightarrow \infty} {x^4+123x^3x^2238x+10^6 \over 34x^438x+11}\] \[\lim_{x \rightarrow \infty} {x^4+123x^3x^2238x+10^6 \over 34x^538x+11}\] \[\lim_{x \rightarrow \infty} {x^7+123x^3x^2238x+10^6 \over 34x^438x+11}\] Lets just talk about what we see going on here. Can you tell me what you notice in the first example? (besides that it looks like a mess :D )
 2 years ago

cwrw238 Group TitleBest ResponseYou've already chosen the best response.0
well  the degree of top and bottom poly's are the same
 2 years ago

cwrw238 Group TitleBest ResponseYou've already chosen the best response.0
sorry i didn't answer earlier  i was called away
 2 years ago

agentc0re Group TitleBest ResponseYou've already chosen the best response.1
It's no problem. And you're correct. The degree of the polynomials are the same on top and bottom. So lets let this rule be our first. If the highest degree polynomials are the same in the denominator as in the numerator, then the limit as it approaches infinity will ALWAYS be the ration of the coefficients. In this case that ratio is \[1\over34\] The reason why this is is if you multiplied the entire equation by \[{1 \over x^4}\over{1 \over x^4 }\] We would then have a lot of cases were there would be some number divided by some form of x. \[1 \over x\] for x= infinity will always go to zero. So on top you would just have 1 + 0  0  0 + 0 and on bottom you would have 34  0 +0 Does that help with the first example? Any questions?
 2 years ago

cwrw238 Group TitleBest ResponseYou've already chosen the best response.0
thanks  no questions  thats very clear
 2 years ago

agentc0re Group TitleBest ResponseYou've already chosen the best response.1
Awesome!!! Lets go to example two. What do you notice there?
 2 years ago

cwrw238 Group TitleBest ResponseYou've already chosen the best response.0
the denominator has higher degree
 2 years ago

agentc0re Group TitleBest ResponseYou've already chosen the best response.1
Right. Do you have a guess as to what might happen?? ... shoot i have to go and i don't want to leave you hanging. A good video about this is: http://patrickjmt.com/limitsatinfinitybasicideaandshortcutsforrationalfunctions/ WHen i get back i can help further explain what's going on if the video doesn't help.
 2 years ago

cwrw238 Group TitleBest ResponseYou've already chosen the best response.0
do we multiply top and bottom by 1 /x^5 ?
 2 years ago

agentc0re Group TitleBest ResponseYou've already chosen the best response.1
For the second example, multiple the top and bottom in the same way we did the first one but do it by the highest degree polynomial. You see that you get 0/(some number). therefor these types of limits when approaching infinity ALWAYS go to zero! how awesome is that?
 2 years ago

cwrw238 Group TitleBest ResponseYou've already chosen the best response.0
yea awesome is right
 2 years ago

cwrw238 Group TitleBest ResponseYou've already chosen the best response.0
ill take a look at the video
 2 years ago

agentc0re Group TitleBest ResponseYou've already chosen the best response.1
I'm back! :D did you have questions still about limits approaching infinity?
 2 years ago

cwrw238 Group TitleBest ResponseYou've already chosen the best response.0
no  i'm checking out the video which is very good. thanks very much for your help
 2 years ago

ParthKohli Group TitleBest ResponseYou've already chosen the best response.1
Also, not to forget mentioning http://khanacademy.com
 2 years ago

cwrw238 Group TitleBest ResponseYou've already chosen the best response.0
@parthkohi oh right  thanks
 2 years ago

ParthKohli Group TitleBest ResponseYou've already chosen the best response.1
You're welcome. Can you please give the medal to @agentc0re? He deserves it all. (:
 2 years ago
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