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Joel Joel
Member since:
January 05, 2008
Total points:
1,982 (Level 3)

Resolved Question

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How do I integrate Cos x Sin x dx?

How do I integrate Cos x Sin x dx? I'm working on an engineering problem and having trouble getting up to speed with simple integral calculus. Any help is much appreciated!
Sridhar R by Sridhar R
Member since:
September 23, 2006
Total points:
11,389 (Level 6)

Best Answer - Chosen by Asker

you can solve in different ways you will get diff answer but they will be right

1) put sinx = t
cosxdx = dt

∫ tdt = t^2/2 +c = 1/2sin^2 X +c

2) sinxcosx = 1/2 sin2x
∫ 1/2sin2x dx = -1/4 cos2x +c
  • 2 people rated this as good
Asker's Rating:
4 out of 5
Asker's Comment:
Great answer --- thanks! The others were great, too, but this answer listed two approaches.
This answer has got the substitution the wrong way round.

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Other Answers (4)

  • Mirhossein Jamali by Mirhossein Jamali
    Member since:
    August 26, 2008
    Total points:
    480 (Level 2)
    cos(x)*sin(x)=1/2 *sin(2x)=>
    int(cosx*sinx*dx)=int(1/2*sin(2x)dx)
    =-1/4*cos(2x)
    • 1 person rated this as good
  • sahsjing by sahsjing
    A Top Contributor is someone who is knowledgeable in a particular category.
    Member since:
    December 19, 2006
    Total points:
    230,483 (Level 7)
    Badge Image:
    A Top Contributor is someone who is knowledgeable in a particular category.
    ∫cosx sinx dx
    = ∫sinx dsinx
    = (1/2)sin^2(x) + c

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