Trigonometric Ratios and the Unit Circle Demo

① This example dynamically demonstrates the geometric meaning of sine, cosine, tangent and other trigonometric ratios as the central angle varies on the unit circle. ② Core concepts: unit‑circle definition of trig functions, ratio definitions (sin, cos, tan), angle measurement in radians and degrees, coordinate geometry relationships among points, segments, distances and angles. ③ Construction highlights: Point creates a movable point on the circle; OrthogonalLine draws the radius perpendicular to the tangent; Intersect finds the projection onto axes; Segment builds the right‑triangle legs; Distance measures leg lengths as function values; Angle measures the central angle α and drives the animation. ④ Suitable for high‑school trigonometry courses, teacher classroom demos, and student self‑exploration.