1. Not finding help here? Sign up for a free 30min 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!

Some-what fancy trig inegral

  1. May 14, 2007 #1
    find the integral of (cosx)^2(tanx)^3

    so first of all i rewrote tan to be (sinx)^3/(cosx)^3 so that i could cancle out the (cosx)^2 on top

    and now i have the integral of (1/cosx)(sinx)^3

    i rewrote that to be (tanx)(sinx)^2...and now i am stuck

    i don't know of any IDs that could make the integral simplier...i am open to suggestions
  2. jcsd
  3. May 14, 2007 #2
    [tex]\frac{\sin^3{x}}{\cos{x}} = \frac{\sin^2{x}sin{x}}{\cos{x}} [/tex]
  4. May 14, 2007 #3
    right...so sinx/cosx would be tanx and that would it it (sinx)^2(tanx).....right?
  5. May 14, 2007 #4
    No. sin^2 would be 1-cos^2
  6. May 14, 2007 #5
    ok let me try that
  7. May 14, 2007 #6
    now i am getting the integral of tanx-sinxcosx

    i know how to integrate sinxcosx but not tanx
  8. May 14, 2007 #7
    That's strange...

    tanx is just sinxcosx, except that the cosx is placed in the denominator. :wink:
  9. May 14, 2007 #8
    oohhh ok...let me try it
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Some-what fancy trig inegral
  1. Evaluate an Inegral (Replies: 0)

  2. Inegration Frustration (Replies: 3)

  3. Definite inegral (Replies: 1)