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Math Help - Isolating a Variable

  1. #1
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    Isolating a Variable

    Hi, I am trying to do this question for a long time now, and i cant figure it out.

    F(x) = 2x^2-x^3; isolate x using any way you can think of.

    P.S: Factoring, and log/Ln doesn't work. I thought this couldn't be solved but apparently it can.
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  2. #2
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    Are you sure factoring doesn't work? I factor x^2 out to get x^2(2-x). So the roots are at x = 0, 2.
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  3. #3
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    solve for x?

    Quote Originally Posted by saurabh91 View Post
    Hi, I am trying to do this question for a long time now, and i cant figure it out.

    F(x) = 2x^2-x^3; isolate x using any way you can think of.

    P.S: Factoring, and log/Ln doesn't work. I thought this couldn't be solved but apparently it can.

    Hi do you mean solve for x? eg. x=2?
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  4. #4
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    I believe they mean to solve for x as a function of F(x) i.e. invert the function. It is cubic in x, so the solution is known, but its not pretty, I can tell you that (Wolfram Alpha can do it).
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  5. #5
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    Quote Originally Posted by saurabh91 View Post
    Hi, I am trying to do this question for a long time now, and i cant figure it out.

    F(x) = 2x^2-x^3; isolate x using any way you can think of.

    P.S: Factoring, and log/Ln doesn't work. I thought this couldn't be solved but apparently it can.
    Dear saurabh91,

    I think you want to subject x in this equation is'nt?? I don't have a hint of how to get the answer but I will let you know when I do. Anyway I will give you the answer which I obtained by using the "Microsoft math".

    Hope this will help you.
    Attached Thumbnails Attached Thumbnails Isolating a Variable-sp1.bmp  
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  6. #6
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    yes i m trying to find the inverse of the function.. with not much success. I tried taking the integral of the function and finding the area of random point (0,1).... the area of the inverse will also be the same so i tried finding the inverse from there but that leaves me nowhere.
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  7. #7
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  8. #8
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    Thank you for the help everyone!
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