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Calculus I problem


09102013, 12:58 PM  #1 
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Calculus I problem
Anyone good in Calculus?
I solved the problem, but I am not sure if I am correct or not. The problem states: Discuss the continuity of f(x)= (x^2+2x3)/(x+3) on interval [5, 2] Since polynomials are continuous everywhere, this particular function is not defined at x=3. Do i just state that the function is continuous everywhere except at x=3 ? Do I have to find one sided limits as well? f(5)= {(5)^2+2(5)3)}/{(2+3)}= 6 f(2) = {(2)^2+2(2)3)}/{(2+3)} = 1 lim x>5+ so I find the limit from the right side and get = 6 lim x>2 and I get = 1 since, my function values equal the limits...does it say the function is continuous everywhere except at x=3?
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09102013, 01:37 PM  #2 
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EDIT I'm wrong
EDIT 2 the limit exists when 5<x<3 and 3<x<2 The limit is defined 6<f(x)<0 and 0<f(x)<1 discontinuity when x=3 let's go with that. Last edited by RandomHero; 09102013 at 02:12 PM. 
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09102013, 02:42 PM  #4 
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After 10 years at a major financial institution, I can confirm that this will never be used in your real life.
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09102013, 03:02 PM  #5 
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After a year of working as an engineer I can also confirm that this will not be needed. With that being said, I forgot everything from Calc I. Sorry

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09102013, 03:20 PM  #6  
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Quote:
Example [Infinity to 4] [2 to +Infinity]
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09102013, 03:24 PM  #7 
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Also, this information maybe needed later in life. For example i never really paid attention in Trigonometry class.
Until recently, i had to write a function that involved trig and calc. I did some personal research and I thought my self much better than i learned in school.
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09102013, 03:42 PM  #8 
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You would simply state that the function is continuous over the ranges [5,3) and (3,2]. More generally, the function is continuous everywhere except for x=3 as you stated, which can formally be written as continuous over the ranges (Inf,3) and (3,+Inf). Just remember, to be rigorous, that you need to use the notation of open set "( )" and closed set "[ ]" to be correct. Infinity is always used with the open set symbol as it can't be contained.
And yea... this stuff is probably never going to be useful to you. The sort of thinking MAY be useful in some areas but it's rare.
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09102013, 03:59 PM  #9  
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Quote:
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09102013, 04:31 PM  #11 
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09102013, 04:35 PM  #12  
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09102013, 04:37 PM  #13 
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Discrete Math is my fav.
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09102013, 04:38 PM  #14 
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Worst class ever: Calc II. Fuck that Taylor Series bullshit

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09102013, 07:38 PM  #17 
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I can confirm as we'll this shit will never be used as an analyst at a Fortune 100 company. Fucking waste of time....I took calc 3...bullshit unless you're going to be a math teacher or some shit.

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09112013, 08:21 AM  #18 
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Or engineer. Had to take all the math classes a math major would minus the little programming courses they have to take. Debated getting a math minor, but figured it'd be useless as an engineer.

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09112013, 09:38 AM  #19  
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same here
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09112013, 10:22 AM  #20  
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I am a fucking engineer and can't remember how to solve that shit
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09112013, 11:35 AM  #21 
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Engineer reporting in. I took up to Calc 4 in college and I can tell you unless you become a Calc professor, no need to remember any of it.
OP, wish I could help but that part of my brain is in retirement.
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09112013, 11:50 AM  #22  
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I do not miss one moment of it. Welcome to hell OP... welcome to hell. 

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