1. The problem statement, all variables and given/known data sinΘ=sin2Θ 2. Relevant equations Double-angle forumla... sin2Θ=2sinΘcosΘ sinΘ=2sinΘcosΘ sinΘ 3. The attempt at a solution sinΘ=2sinΘcosΘ sinΘ-2sinΘcosΘ=0 sinΘ(1-2cosΘ)=0 Now I'm getting stuck because 1-2cosΘ is not an identity of any sort. Any help would be appreciated...thanks!