Geometric Proof and Construction of the Half-Angle Formula (R.J. Walker)

This applet demonstrates R.J. Walker's geometric construction of the half-angle formula. Using midpoints, segments, semicircles, and polygons, it visually illustrates the geometric meaning of half-angle formulas in trigonometry. Integrating rectangles and inscribed circles, it helps learners understand the half-angle relationships of trigonometric functions and their geometric applications.