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: Help with a trig integration

  1. May 19, 2010 #1
    1. The problem statement, all variables and given/known data
    integrate tan(x)sec^4(x) dx

    2. Relevant equations

    3. The attempt at a solution
    int tan(x)sec^4(x) dx
    = int tan(x)sec^2(x)sec^2(x) dx
    = int tan(x)sec^2(x) (tan^2(x)+1) dx

    let u = tanx ==> du = sec^2(x) dx

    = int usec^2(x) (u^2 + 1) /sec^2(x) du
    = int u(u^2+1) du
    = u^4/4 + u^2/2 + C
    and then replace the u with tanx

    am i doing this correct?
  2. jcsd
  3. May 19, 2010 #2

    Char. Limit

    User Avatar
    Gold Member

    Absolutely. If you want, you can unfactor the answer, but it isn't necessary.
  4. May 19, 2010 #3
    ttthank you!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook