We have the form
y = Asin (Bt + C) + D
A is the amplitude.......it is the difference between the highest and lowest point divided by 2 = 20/2 = 10
B is the period......we can find this as follows
B = 2pi/period......the period is 8 seconds.....so we have 2pi / 8 = pi/4
C= the phase shift ....since the first point is on the midline which is y = 0.....this is the normal starting point for the sine function....so.....there is no phase shift
D = shift up/down.......there is none since the first point is on the midline, y = 0
Thus....the function is
y = 10 sin ( (pi/4) t)
Here is a graph :https://www.desmos.com/calculator/queeoexbii
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