Complex Number Addition: Geometric Vector Sum and Parallelogram Rule

① This GeoGebra example dynamically demonstrates the geometric meaning of adding two complex numbers, showing how their corresponding vectors combine in the complex plane via the parallelogram rule. ② The core mathematical concept is complex addition, treating complex numbers as plane vectors; the sum's endpoint represents the resulting complex number, involving the complex plane, vectors, modulus, and argument. ③ Construction highlights: uses the ComplexVector command to create vectors for complex numbers, ComplexAddition to compute the sum directly, and Segment to connect points forming a parallelogram or triangle; objects include z_1, z_2, u, v, C, z, a, b, allowing real-time dragging to observe changes. ④ Suitable for high school and early college students learning the relationship between complex numbers and vectors, and for teachers as a classroom demonstration to bridge algebraic operations with geometric intuition, also linking to vector space concepts in linear algebra.