# Math Help - sin of 2 theta

1. ## sin of 2 theta

If theta equals .79, do we multiple .79 by 2 before finding the sine, or do we find the sine and then multiply by 2?

2. ## Re: sin of 2 theta

sine of 2 theta is denoted by

$\sin (2 \theta)$

And the multiplication happens before the sine is applied.

There is an identity (which I'm guessing you haven't learned yet)

$\sin (2 \theta) = 2\sin(\theta) \cdot \cos(\theta)$