Definition of Derivative - Task 2: Dynamic Secant to Tangent

① This example dynamically demonstrates the geometric meaning of the derivative as the instantaneous rate of change by showing how a secant line approaches a tangent line as the interval shrinks. ② Core mathematical concepts include the definition of the derivative, limits, secant slope, tangent slope, and local linear approximation. ③ Construction highlights: uses GeoGebra's Textfield and InputBox for interactive input, If for conditional logic, Tangent and Line commands to create tangent and secant lines, and Polygon to form auxiliary triangles. Key objects include function f, moving point A, parameter h, secant slope b, and input boxes to adjust h, allowing users to observe the limiting process. ④ Suitable for high school calculus introduction or college-level basic calculus, ideal for classroom demonstrations or student self-exploration to grasp the limit-based definition of derivatives.