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Homework Help: Integration by substitution

  1. Oct 20, 2006 #1
    evaluat the indefinite integral ((sin(x))/(1+cos^2(x)))dx

    I let

    u = 1 + cos^2(x)

    then du = -sin^2(x)dx

    I rewrite the integral to

    integral (du)/sqrt(u)

    can I set it up like this? should I change u to something else?

    I also tried it like this by rewriting the original equation to:

    indefinite integral ((sin(x))/(1+cos(x)cos(x)))dx

    u = cos(x)

    du = -sin(x)dx

    then

    - integral (du)/(1+(u^2))

    Also, can somebody give me directions on how to format equations in this message board to make my questions somewhat clearer.


    Thanks alot!

    I actually tried to evaluate it using one of my methods and arrived at the following result:

    2((1+cos^2)^(1/2))+C
     
  2. jcsd
  3. Oct 20, 2006 #2
    Do not post the same thread twice. Your earlier thread has been answered.
     
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