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Homework Help: Square root

  1. Jul 15, 2006 #1
    sqrt(81t^4 + 18t^2 +1).can anybody teach me how to factorise this eqn so that the sqrt can be done pls

    thanx
     
  2. jcsd
  3. Jul 15, 2006 #2
    i need to integrate this eqn w.r.t (t).
    pls help
     
  4. Jul 15, 2006 #3

    nazzard

    User Avatar
    Gold Member

    Hello teng,

    make use of the binomial theorem.

    [tex](a+b)^2=a^2+2ab+b^2[/tex]

    The coefficient 81 should be a good hint already. :wink:

    Regards,

    nazzard
     
    Last edited: Jul 15, 2006
  5. Jul 15, 2006 #4

    nazzard

    User Avatar
    Gold Member

    After you made use of the binomial theorem you will have to integrate a polynomial in t. Do you know how to do that?

    Regards,

    nazzard
     
  6. Jul 15, 2006 #5
    If the t^4 bothers you, substitute t^2 = r in the equation and then factorize the quadratic form. Don't forget to revert to t before you integrate.
     
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