1. ## Cosine

If cosθ = 0.6, then cos(θ + ) = ?

How would I start this problem?
Thanks for your help!

2. Originally Posted by live_laugh_luv27
If cosθ = 0.6, then cos(θ + ) = ?

How would I start this problem?
Thanks for your help!
$cos(\theta+\pi) = -cos(\theta)$