(snip)
Neat. You can also get it by integrating by parts just once:
Int(sinx.sinx dx) = sinx.(-cosx) + Int(cos^2 dx)
(using u = sinx, dv = sinx dx).
Then use cos^2 = 1 - sin^2, so you get:
2*Int(sin^2 dx) = Int(1.dx) - sinx.cosx
Int(sin^2 dx) = (1/2)*x - (1/4)*sin2x
(using sin2x = 2 sinx cosx).
mark snyder
****************************************************************************
* To post to the list: email mathedcc@archives.math.utk.edu *
* To unsubscribe, send mail to: majordomo@archives.math.utk.edu *
* In the mail message, enter ONLY the words: unsubscribe mathedcc *
* Words in the Subject: line are NOT processed! *
* Archives at http://archives.math.utk.edu/hypermail/mathedcc/ *
****************************************************************************