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Math Help - Equations with fractional exponents.

  1. #1
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    Equations with fractional exponents.

    I have to solve a few equations that are similar to radial equations. I know how fractional exponents relate to square roots but I have something majorly wrong in my operations. I can't solve any of these. Here's one I could use help with. If I see enough steps I can easily apply it to the rest.

    5x^5/3 +160=0

    It's supposed to read 5x to the 5/3rd power.

    I have a test tomorrow and I'm trying to get a grip on some of this stuff that I'm not understanding. Oddly enough I can handle quadratics with fractional exponents already, I just can't do this simpler version.
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    Quote Originally Posted by Turtle13 View Post
    I have to solve a few equations that are similar to radial equations. I know how fractional exponents relate to square roots but I have something majorly wrong in my operations. I can't solve any of these. Here's one I could use help with. If I see enough steps I can easily apply it to the rest.

    5x^5/3 +160=0

    It's supposed to read 5x to the 5/3rd power.

    I have a test tomorrow and I'm trying to get a grip on some of this stuff that I'm not understanding. Oddly enough I can handle quadratics with fractional exponents already, I just can't do this simpler version.
    you mean 5x^{5/3} + 160 = 0 ?

    Note that this means x^{5/3} = -32

    raise both sides to the 3/5 power (do you see why?) you get

    x = (-32)^{3/5}

    which i think you can finish off
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    Yes, that helps immensely. I was able to solve them all with no problems.

    BTW, how do I properly type that fractional exponent with the math brackets?
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    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by Turtle13 View Post
    Yes, that helps immensely. I was able to solve them all with no problems.

    BTW, how do I properly type that fractional exponent with the math brackets?
    if an argument or power has more than one elements in it, you must include it is {} brackets.

    [tex]x^2/3[/tex] gives x^2/3

    while

    [tex]x^{2/3}[/tex] gives x^{2/3}
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  5. #5
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    Quote Originally Posted by Jhevon View Post
    if an argument or power has more than one elements in it, you must include it is {} brackets.

    [tex]x^2/3[/tex] gives x^2/3

    while

    [tex]x^{2/3}[/tex] gives x^{2/3}
    Or....

    [tex]x^{\tfrac{2}{3}}[/tex] gives you x^{\tfrac{2}{3}}, but I kinda like yours better. It's easier to read.
    Last edited by masters; January 26th 2010 at 01:59 PM.
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    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by masters View Post
    Or....

    [tex]x^{\frac{2}{3}}[/tex] gives you x^{\frac{2}{3}}, but I kinda like yours better. It's easier to read.
    indeed, i usually use \frac in a power only if the base is huge, like \left( \frac {x^3 + 4x + 1}{2x  + 3} \right)^{\frac 23}


    in that case, the power might look too small, so you can use \tfrac: \left( \frac {x^3 + 4x + 1}{2x  + 3} \right)^{\tfrac 23}
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  7. #7
    A riddle wrapped in an enigma
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    Quote Originally Posted by Jhevon View Post

    in that case, the power might look too small, so you can use \tfrac:
    Yeah, \tfrac looks better.

    \frac: x^{\frac{2}{3}}

    \tfrac: x^{\tfrac{2}{3}}
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