1. The problem statement, all variables and given/known data Show that sin 600° . cos 330° + cos 120° . sin 150° = - 1 2. Relevant equations I know that sinΘ = opposite/hypotenuse and cosΘ = adjacent/hypotenuse. 3. The attempt at a solution I am equipped with knowledge about what sinΘ and cosΘ is from right angled triangle. I stand in front of a wall and visualize opposite side, adjacent side and hypotenuse but I am unable to clearly picture what sin 600° . cos 330° + cos 120° . sin 150° = - 1 mean. What is the meaning of the equation? What is the meaning of -1 on the right hand side of the equation?