1. The problem statement, all variables and given/known data sin²(1°)+sin²(3°)+sin²(5°)+.......sin²(359°)= ? And : 1!+2!+3!+4!+.....+2006!, asked are he last two numbers of this sum. 2. Relevant equations I don't know any 3. The attempt at a solution I don't know how to calculate Sin with your head, and 2006! is way to hard to calculate. Is there a simple formula for these questions?