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Math Help - I was good at math until i was introduced to limits. PLEASE HELP

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    How do i know when to plug limit into my calculator or solve algebraicaly

    I NEED HELP FINDING LIMITS ALGEBRAICALLY
    lim t^3+8/t+2 t-->-2
    Last edited by dusech3; November 18th 2012 at 11:06 AM.
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    Re: I was good at math until i was introduced to limits. PLEASE HELP

    Quote Originally Posted by dusech3 View Post
    I NEED HELP FINDING LIMITS ALGEBRAIALLY
    Post a problem. No mind readers here.
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    Re: I was good at math until i was introduced to limits. PLEASE HELP

    lim tan3x/tan5x
    x--->0
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    Re: I was good at math until i was introduced to limits. PLEASE HELP

    For the first limit, try writing the numerator as the sum of 2 cubes.

    For the second, barring the use of L'H˘pital's rule, try writing:

    \frac{\tan(3x)}{\tan(5x)}=\frac{3}{5} \cdot \frac{ \tan(3x)}{3x} \cdot \frac{5x}{ \tan(5x)}
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    Re: How do i know when to plug limit into my calculator or solve algebraicaly

    Quote Originally Posted by dusech3 View Post
    I NEED HELP FINDING LIMITS ALGEBRAICALLY
    lim t^3+8/t+2 t-->-2
    The first thing you should try, to find \lim_{x\to a} f(x) is calculating f(a). That doesn't work for this problem because both numerator and denominator are 0. And that t^3+ 8 is 0 when t= -2 [b]tells/b] you that it has a factor of t+ 2. That is, t^3+ 8= (t+ 2)(t^2+ at+ b) for some a and b. What are they?
    Last edited by HallsofIvy; November 18th 2012 at 12:00 PM.
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