The function cos(theta) gives the x-coordinate of a point on the unit circle as the angle theta increases, creating a smooth wave that repeats every 2 pi units. It ranges from -1 to 1 and has a familiar wave-like shape. Cos(2theta), on the other hand, is a version of the cosine function that oscillates twice as fast—it completes two full cycles in the same interval where cos(theta) completes one. This is because the angle inside the cosine is doubled, compressing the wave. Cos(2theta) is often u