The Student Room Group
Reply 1
This is integration by recognition.

When you have an integral of the form f(g(x))g(x)f(g(x))g'(x) you can see that the g(x)g'(x) has come about as a result of the chain rule. Think of integration as the inverse of differentiation. What would differentiate to give you that? Do not worry about constants too much, they can be corrected at the end.

Additionally, this sort of question should go in study help, not Exams and Qualifications =)
Reply 2
Try a substitution. u= cosx or u=sinx
Reply 3
malolis
Try a substitution. u= cosx or u=sinx

It would have to be u=sinxu = \sin x, otherwise it doesn't really work.
Reply 4
cheers .. intergration by substitution. thanks guys

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