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Homework Help: Find the area between two curves - Help finding the limits of integration - Again

  1. May 1, 2010 #1
    1. The problem statement, all variables and given/known data

    The curves are:

    [tex] y = \frac{x^{4}}{x^{2}+1} [/tex]


    [tex] y = \frac{1}{x^{2}+1} [/tex]

    3. The attempt at a solution

    So again I assume that:

    [tex] \frac {x^{4}}{x^{2}+1} = \frac {1}{x^{2}+1} [/tex]

    and then cross multiply:

    [tex] (x^{2}+1) = x^{4}(x^{2}+1) [/tex]

    not really sure at this point if i should distribute the x^4 but if i do it looks like so:

    [tex] (x^{2}+1) = (x^{6}+x^{4}) [/tex]


    [tex] (x^{2}+1)-(x^{6}+x^{4}) = 0 [/tex]

    and I am not really sure what to do at this point, I do have a polynomial if I do the subtraction which is:

    [tex] -x^{6}-x^{4}+x^{2}+1 = 0 [/tex]

    but I don't know how to factor it....

    thanks guys!
  2. jcsd
  3. May 1, 2010 #2


    Staff: Mentor

    Don't cross multiply. Multiply both sides by x^2 + 1.
  4. May 1, 2010 #3
    thanks man, worked out, but I am having a WAY hard time trying to do this problem so I will post the actual problem another thread. thanks for the help here though.
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