Question 1111960
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Since we are starting at its highest point, we can use a cosine function with no horizontal shift.<br>
The maximum value is 6.5; the minimum is 0.5.  That means an amplitude of 3 and a center line of 3.5.<br>
The equation is then
{{{3cos(kx)+3.5}}}
where the horizontal compression factor k is 2pi divided by the period.  Since the period of the windmill's rotation is 8 seconds, the equation is
{{{3cos((2pi/8)x)+3.5}}}<br>
Here is a graph of 4 periods, including the specified interval from 0 to 24 seconds:<br>
{{{graph(400,200,-4,28,-2,8,3cos((2pi/8)x)+3.5)}}}<br>
Since the period is 8 seconds, the height at 135 seconds will be the same as the height at 7 seconds:
{{{3cos(14pi/8)+3.5 = 5.62132}}}