Step-by-step explanation:
Waves have the form:
y = A sin (2π/T x + φ) + B
where A is the amplitude (the distance from the center of the wave to the max or min),
T is the period (time it takes for one cycle),
φ is the phase shift (moves the wave left or right),
and B is the offset (moves the wave up or down).
This can also be written with cosine.
Here, we have d = 6 cos(π/2 t).
The amplitude is A = 6, so the maximum distance from the equilibrium position is 6 units.
The period is:
2π / T = π/2
T = 4
So the period is 4 seconds.
