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Math Help - Limits Help

  1. #1
    Junior Member
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    Limits Help

    1) lim (1/x) - (1/2) / (x-2)
    x->2

    I know to multiply by (1/x)+(1/2) to both top and bottom but I don't know how...can some help with a step by step how?

    2) lim (4+h)^3 - 64 / h
    h->0

    I tried sum of cubes and got lost haha. I did the steps in that but the 64 is messing me up.

    Any help would be great
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  2. #2
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by Dickson View Post
    1) lim (1/x) - (1/2) / (x-2)
    x->2

    I know to multiply by (1/x)+(1/2) to both top and bottom but I don't know how...can some help with a step by step how?
    that's not what i'd do.

    i suppose you mean, \lim_{x \to 2} \frac {\frac 1x - \frac 12}{x - 2} ??

    in that case, just combine the fractions in the numerator and simplify

    if you want to multiply the top and bottom by something, multiply by 2x (the LCD of the fractions in the numerator). it's the equivalent of combining the fractions

    2) lim (4+h)^3 - 64 / h
    h->0

    I tried sum of cubes and got lost haha. I did the steps in that but the 64 is messing me up.

    Any help would be great
    well, what can i say, but try again. make sure you have the right formula this time. it helps to write out the formula using letters, like a to represent (4 + h) and b to represent 4 ( 64 = 4^3) then erase them and write in he expressions and simplify
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