1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Trig integral

  1. Mar 2, 2008 #1
    1. The problem statement, all variables and given/known data
    [tex]\int tan^5(6x) sec^3(6x) dx[/tex]



    2. Relevant equations



    3. The attempt at a solution
    first off I set u=6x to get 1/6[tex]\int tan^5(u) sec^3(u) dx[/tex]
    then I used trig identities to put tangent in terms of secant and I came up with

    [tex]\int sec^9(u)-3sec^7(u)+3sec^5(u)-sec^3(u) dx[/tex]
    Not sure where to go from here, or if I'm doing this the right way
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Mar 2, 2008 #2
    Watch your substitutions.

    [tex]\frac 1 6\int\tan^{5}u\sec^{3}udu[/tex]

    [tex]\frac 1 6\int\tan^{4}u\sec^{2}\sec u\tan udu[/tex]

    *[tex]\tan^{2}u+1=\sec^{2}u[/tex]

    Take it from here.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook




Loading...