How do you apply the double angle formula for $sin 8x cos 8x$ ?

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Answer 1 · 2015-04-26T16:35:04

Think about double angle formulas until you think of one that might be useful.

$sin 2 theta = 2 sin theta cos theta$

That looks helpful.

$2 sin theta cos theta = sin 2 theta$

so
$sin theta cos theta = 1/2 sin 2 theta$

And
$sin 8x cos 8x = 1/2 sin 16x$

How do you apply the double angle formula for sin 8x cos 8xsin 8x cos 8x?