graphs of sine and cosine?

Question

A point is moving with constant speed alonga circle of radius 3 shown in the figure. When T=0 the point is at A and moves counterclockwise. Find the equation of position of the projection of this point over the horizontal diameter AC x(t) and sketch the graph corresponding to the interval of time from the start until it goes around the circumference two times. Consider that the point takes 2pi seconds to get from A to C.




C·················································l····································o A

Answer 1

x = 3 cos(t / 2)
The cosine argument is in radians, not degrees.

x = 3 cos( 90t / pi)
if the argument is in degrees

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