1. The problem statement, all variables and given/known data A 215 g mass attached to a horizontal spring oscillates at a frequency of 5.20 hz. At t=0 s, the mass is at = 4.00 =cm and has velocity 26.0 cm/s. Determine the Amplitude. 2. Relevant equations x(t)=ACos(2(pi)t)/T 3. The attempt at a solution Well at t=o x=4, but then the 2(pi)t goes to zero and the whole equation equals 0. What am I doing wrong? Thanks for any and all help And yes sorry units would help so there they are.