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: Integrate int (sin^2(t) + cos^2(t) -1)dt from e^x to e^(2x)

  1. Mar 19, 2008 #1
    1. The problem statement, all variables and given/known data

    Integrate from e^x to e^2x: (sin^2(t) + cos^2(t) -1)dt

    2. Relevant equations
    just standard integral equations

    3. The attempt at a solution

    I know how to do most of it, my only question is: is (sin^2(e^2x) + cos^2(e^x) -1) a special trig identity? or would i just solve it like a normal interation in parts problem?
  2. jcsd
  3. Mar 19, 2008 #2
    well it seems trivial to me... lol
    This question seems to be just tricky, nothing else.
  4. Mar 19, 2008 #3
    Aren't the sin and cos together adding to 1 the way you've written it, thus 1-1=0 ? You may want to double check you have it correct
  5. Mar 19, 2008 #4

    What does this equal to??
  6. Mar 19, 2008 #5
    ok, thanks guys lol. I feel dumb now
  7. Mar 19, 2008 #6
    Ok, integrate the following:

    [tex]\int_0^{ln(1)} sin(x)e^{-x^{2}}dx[/tex]

    This question was somewhere i dunno where though. Give a shot to it.

    HINT: THis is also tricky.
    Last edited: Mar 19, 2008
  8. Mar 19, 2008 #7

    Isnt that just equal to 1?
  9. Mar 19, 2008 #8
    Look at your limits of Integration

    From 0 to Ln(1)
  10. Mar 19, 2008 #9
    Why on earth do u think it is equal to 1?
  11. Mar 19, 2008 #10
    How did u change your display name?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook