Coordinates #1: Unit Circle Point and Vector Tracing

① This example demonstrates the relationship between coordinates, angles, and vectors by placing a point A on the unit circle and tracing its motion, along with related points and vectors. ② Core mathematical concepts include the Cartesian coordinate system, unit circle, trigonometric functions (sine and cosine), vectors, and coordinate representation of points. ③ Construction highlights: using GeoGebra to create point A (movable on the unit circle), point B (likely a projection or related point), enabling the trace feature to record A's path, and generating object A_1 (possibly coordinate readout or vector representation) to dynamically show coordinate changes. ④ Suitable for upper middle school to high school students, this example helps visualize the link between coordinates and trigonometry, and serves as an introductory tool for analytic geometry or vector lessons.