sin8x= (8sinx)(cosx)(cos2x)(cos4x)
i have been trying the double angle formula on sin8x and not having any luck any help is appreciated!
sin(8x) = sin2(4x)
you should know that sin2x = 2sinxcosx. Applying this to the above, you have
sin2(4x) = 2sin(4x).cos(4x)
again,
sin(4x) = sin2(2x) = 2 sin(2x)cos(2x), so you have,
sin(8x) = 2 [ 2 sin(2x)cos(2x)] cos(4x) = 4 sin(2x)cos(2x)cos(4x)
again put sin2x = 2sinxcosx in the above, and you have your answer
Hello, superhume!
We can work it from the right side . . .Prove: .
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We can work it from the left side . . .
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