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Reyjuanx10
ʃsin 3x sin 6x dx
r u familiar with this formula? cosc-cosd=2sin(c+d)/2sin(d-c)/2? here c=A+B and d=A-B
hmmm I'd prefer to use identities. I can't seem find an identity for sin 6x
how about the double angle sin(2x) = 2 sin(x) cos(x)
u can use the one i showed. cosc-cosd=2sin(d-c)/2sin(c+d)/2 c+d/2=6x c-d/2=3x u can find c and d from this
(c+d)/2=6x (c-d)/2=3x