Geometric Proof of the Double Angle Tangent Formula

This GeoGebra example demonstrates a geometric proof of the double angle tangent formula tan(2α) = 2tan(α)/(1-tan²(α)). Using geometric constructions involving rays, circles, angles, orthogonal lines, and reflections, it builds a figure with multiple angles (α, β, γ, δ, etc.) to visually illustrate the derivation and geometric meaning of this trigonometric identity. The example transforms an algeb