1. The problem statement, all variables and given/known data Well I have a couple trig questions that are most likely very simple, but I can't really remember the theory behind them. The first is: sin(pi)/2. I asked my teacher how to find this and he told me to just remember it was sqrt(2)/2. The thing is, I'd like to understand why this is true. I have been searching the internet and have found some things but I just need a simple explanation of what the sin function actually does. The other problem is: 1/(1-cos(2*pi). This one I'm really at a loss for how to solve for the same reason as the first one, I just don't understand the math. 3. The attempt at a solution I know that sin(pi)/2=sqrt(2)/2, so I have the solution, I would like to understand it though. The second question, I don't even know where to start, so if anyone could explain the method I could give it a shot. Thanks for your help.