1. The problem statement, all variables and given/known data This is for a math based physics class. I need the equation ofa pendulum and of a spring. 2. Relevant equations Spring: x=Asin(wt-phi)+B Pendulum: theta=theta0cos(wt+phi) or theta=theta0cos(sqrt(g/l)sin(theta)) 3. The attempt at a solution I don't know which of these are correct. Please let me know the right equation for each; if it's a differential equation, please let me know what it is solved if possible. Thank you.