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Homework Help: Trig subst.

  1. Jul 7, 2009 #1
    1. The problem statement, all variables and given/known data
    I(1/(9x^2+6x-8)^(1/2),x)
    I( 1/( (3x+1)^2-9 )^(1/2),x )
    3x+1=3secT
    dx=secTtanTdT
    I( (secTtanT)/3tanT,T )
    (1/3)I( secT,T)
    (1/3)|secT+tanT|+C
    secT=(3x+1)/3
    tanT=(9x^2+6x-8)^(1/2)/3
    solution: (1/3)|(3x+1)/3+(9x^2+6x-8)^(1/2)/3|
    my book is showing :(1/3)|(3x+1)+(9x^2+6x-8)^(1/2)|


    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Jul 7, 2009 #2
    Double-check these steps.
     
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