a) Determine a sinusoidal equation to model the vertical position, in metres, of the boat versus the time, in seconds.

b) Use your model to determine when, during each cycle, the boat is 0.5m above its mean position. Round your answers to the nearest hundredth of a second.

How do you know if it is sin, cos, tan, sec, csc, or cot?

Also i'm kinda just lost for b

Solve in radians please