1. The problem statement, all variables and given/known data Show that (sin(2theta) - sin(theta)) / (cos(2theta) - cos(theta) + 1) = tan(theta) sorry if this setting out is unclear but i am not familiar with how to post math symbols and such. 2. Relevant equations above 3. The attempt at a solution I have tried simplifying using double angle formulae but it seems i am going backwards instead of forwards. This is really frustrating as it seems to be quite simple but when I try to solve, i get nowhere. Thanks.