# Math Help - write the expression as the sine, cosine , or tangent of an angle

1. ## write the expression as the sine, cosine , or tangent of an angle

2 sin100 cos 100
any suggestion? thanks in advance

2. Originally Posted by alessandromangione
2 sin100 cos 100
any suggestion? thanks in advance
Dear alessandromangione,

$2sin\theta\cos\theta=sin2\theta$

Therefore,
$2sin100^{o}cos100^{o}=sin(2\times100^{o})=sin200\a pprox-0.3420$