Partical Fractions

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

    Turn this into partial fraction.
    k1b1/[((k1+b1*s)(k2+b2*s))-b1[tex]^{2}[/tex]s[tex]^{2}[/tex]]

    2. Relevant equations

    n/a

    3. The attempt at a solution

    original question was to find the transfer function with springs and a damper and I reduced it to this far but I cant get the partial fraction.
    once i get that partical fractions, i take the inverse laplace transform and get the answer.
     
    Last edited: Mar 10, 2008
  2. jcsd
  3. I'm getting dizzy reading it ...

    [tex]\frac{k_1b_1}{(k_1+b_1s)(k_2+b_2s)-b_1^2s^2}[/tex]

    Yes?
     
  4. yeap :)
     
  5. well is this impossible to separate?
    i did other problems but i am just stuck on this one.
    let me know if you need the actual problem statement...
     
  6. HallsofIvy

    HallsofIvy 40,242
    Staff Emeritus
    Science Advisor

    you want, of course, to factor the denominator. I think I would be inclined to multiply out that first part and combine coefficients of like powers. It will be, of course, a quadratic. At worst, you could set the denominator equal to 0 and solve the equation by the quadratic formula.
     
  7. tiny-tim

    tiny-tim 26,054
    Science Advisor
    Homework Helper

    [tex]\frac{k_1b_1}{(k_1+b_1s)(k_2+b_2s)-b_1^2s^2}[/tex]

    krnhseya, just expand the bottom line into the form [tex]as^2\,+\,bs\,+\,c[/tex], and then factor it using the good ol' (-b ±√b^2 - 4ac)/2a. :smile:
     
  8. well that b1 squared and s squared at the end...it cancells the expansion of the squared part...
     
  9. tiny-tim

    tiny-tim 26,054
    Science Advisor
    Homework Helper

    No, it doesn't …

    It's [tex]k_1k_2\,+\,(b_1k_2\,+\,b_2k_1)s\,+\,b_1(b_2\,-\,b_1)s^2[/tex]
     
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