How do you express $sin(pi/12) * cos((3pi)/8 )$ without products of trigonometric functions?

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Answer 1 · 2016-03-24T00:09:14

$\sin(\pi/12)\cos(3\pi/8)$

$=(1/2)(\sin(11\pi/24)-\sin(7\pi/24))$

Use these identities to simplify this kind of product:

$\sin(a)\sin(b)$

$=(1/2)(\cos(a-b)\cos(a+b))$

$\sin(a)\cos(b)$

$=(1/2)(\sin(a+b)+\sin(a-b))$

$=(1/2)(\sin(a+b)-\sin(b-a))$

$\cos(a)\cos(b)$

$=(1/2)(\cos(a+b)+\cos(a-b)$

How do you express sin(pi/12) * cos((3pi)/8 ) sin(pi/12) * cos((3pi)/8 ) without products of trigonometric functions?