# Math Help - solving for theta

1. ## solving for theta

Can someone just get me started on this problem? Thanks.

2cos(theta)-sin2(theta)=0

I tried to substitute 2sin(theta)cos(theta) for the sin2(theta), but that didn't really get me anywhere.

2. $2\cos(\theta)-\sin(2\theta)=0$

$2\cos(\theta)-2\sin(\theta)\cos(\theta)=0$

now factor and divide

$2\cos(\theta)(1-\sin(\theta))=0$

$1-\sin(\theta)=0$

$\sin(\theta)=1$

Can you solve it now?

3. How did you get from the second line to the 3rd line?

4. I took out $2\cos(\theta)$ as a common factor in the left hand side.

5. Got it now. Thanks!