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Math Help - Make x the subject of y(x^2+a^2)=a^3

  1. #1
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    Make x the subject of y(x^2+a^2)=a^3

    Make x the subject of y(x^2+a^2)=a^3
    Many Thanks!
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  2. #2
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    Quote Originally Posted by BabyMilo View Post
    Many Thanks!
    You want to solve y(x^2+ a^2)= a^3 for a.

    Okay, multiplying the left side, x^2y+ a^2y= a^3 which is the same as a^3- ya^2- x^2y= 0. That is a cubic equation and there is a formula for the solution- unfortunately, it is very complicated.

    Look at Cubic Formula -- from Wolfram MathWorld
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  3. #3
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    I appreciate your help! But I am just making x the subject (like rearranging the equation). Many Thanks!
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  4. #4
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    Quote Originally Posted by BabyMilo View Post
    I appreciate your help! But I am just making x the subject (like rearranging the equation). Many Thanks!
    Divide by y. Subtract a^2. Take the square root.
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  5. #5
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    Quote Originally Posted by mr fantastic View Post
    Divide by y. Subtract a^2. Take the square root.
    so would it be? x=sq root of (a^3/y)-a^2 Many THanks!
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  6. #6
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    Quote Originally Posted by BabyMilo View Post
    so would it be? x=sq root of (a^3/y)-a^2 Many THanks!
    You need \pm \sqrt{}
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