1. The problem statement, all variables and given/known data It seems like a pretty straightforward equality but I when I tried to google it doesn't seem like it is known at all. All the paths I have tried have been dead ends. The question was initially: Find the limit as x approaches 0 for the expression (1-cosx)/x^2 In the second step of the solution, the expression became (2(sin^2)*(x/2)) / x^2 and I didn't know how the numerator changed to that new expression. Thank you for your help!