Question

Find the sinusoidal function.
http://prnt.sc/ctq56d

Answer 1

some confusion in the question - t is time in seconds
it then says t should be in radians...

Answer 2

The general equation is:
D(t)=a sin(bt)+d
where
a is the vertical scale factor (stretches when a>1)
1/b is the horizontal scale factor (stretches when 1/b>1)
d is the vertical shift (up when d>0)
The parent function is sin(t) when a=b=1, d=0.

As in all geometry problems, drawing the diagram is half the solution.

Use the diagram together with the notes given earlier, figure out the values of a, b and d to find the equation of the function, D(t).