Demonstration of the Definition of a Derivative

This example demonstrates where the definition of a derivative comes from. It visually explains the geometric meaning of the derivative by showing the limiting position of a secant line as two points on the function graph approach each other. The core math concepts involved are derivatives, function graphs, and limits. The construction uses GeoGebra commands such as Function, Point, Line, Segment, and Tangent, with points A and B moving along the function, forming a secant line that eventually approaches a tangent line. It is suitable for high school and above students to learn and understand the definition and geometric background of derivatives.