Hi, I was doing a question with this simple integral
so rather than do it by parts (which probably would turn out to be double back on itself so you get the integral again), I opted for using sin2x = 2sinxcosx
so that means the integral simplified to
which integrates to
so wack in the limits and I get 3a[1-1] = 0
but that isn't right is it?
The answer scheme suggest =
but i) How come my method doesn't work
ii) How can the mark scheme do that. You can't just do that!?