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: Integral of sec3xtan3xdx

  1. May 13, 2010 #1
    integral of sec3xtan3xdx

    i tried to start this by rewriting secx as 1/cosx and that got me the integral of sin2x/cos6xdx

    after that i tried a regular substitution but that didnt work since it doesnt take care of the sin3x on top

    kinda stuck on where to go
    any help?
     
  2. jcsd
  3. May 13, 2010 #2

    gabbagabbahey

    User Avatar
    Homework Helper
    Gold Member

    Re: integral

    Hint: [itex]\sin^3(x)=\sin(x)[1-\cos^2(x)][/itex] :wink:
     
  4. May 13, 2010 #3
    Re: integral

    I would try: sec2x(sec x)(tan2x)(tan x)
     
  5. May 13, 2010 #4
    Re: integral

    first guys idea worked, thanks
     
  6. May 13, 2010 #5

    thrill3rnit3

    User Avatar
    Gold Member

    Re: integral

    tan2x = sec2x-1
     
  7. May 13, 2010 #6
    Re: integral

    I know, just showing you another way of going about it, with thrill3rnit3 giving you a huge hint on how to go about it.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook