Dynamic Proof of Pythagorean Trigonometric Identity

This example dynamically demonstrates the geometric meaning of the fundamental Pythagorean trigonometric identity using the unit circle, visually linking the Pythagorean theorem with trigonometric functions. Key math concepts include the unit circle, trigonometric definitions, vector and distance calculations. It is constructed using GeoGebra commands like Center, Point, Segment, Intersect, Polygon, Angle, Vector, Distance, with objects such as r, c, A, B, a, b, d, C, poly1, b_1, a_1, c_1, α, D, θ, u, v for dynamic transformations and measurements. Suitable for high school mathematics teaching to enhance understanding of trigonometric identities and geometric intuition.