1. The problem statement, all variables and given/known data How can one model the vertical and horizontal motion of a swing? The maximum height was 258 cm, the lowest 38cm and the horizontal movements went from 2.39m on the left to 2.44m on the right. The period was approx 2.5793 seconds. (The data was hand collected, so it is not perfect) 2. Relevant equations knowledge of sine and cosine functions 3. The attempt at a solution So I set up a periodic equation for the x movement as x=2.415sin(2pi/2.5793 T) using the data above and then for y, y=-1.48cos(pi/2.5793 T) + 1.86. This results in a circle if the T values get large enough. So to compensate, I restricted the domain, and got a semi circle. However, there are still -T values, which makes no sense as one cannot have negative time. Is there a more accurate way to do this or any way to shift the graph to the right, to avoid negative T's?