Rectangle Approximation Method for Area Under a Curve

① This example dynamically approximates the area under a function curve using rectangles, visually demonstrating the geometric meaning of definite integrals. ② Core mathematical concepts include Riemann sums, definite integrals, function graphing, interval partitioning, and the limit process. ③ Construction details: GeoGebra commands such as Textfield for inputting function and interval endpoints, RectangleSum to generate the rectangle sum, and a slider n to control the number of rectangles; objects include function f, endpoints a and b, slider n, text elements text1/2/3, and the area value. ④ Suitable for high school to early college students, this is ideal for introductory calculus lessons, helping learners grasp the idea of partition, approximation, summation, and limit, and explore how the number of rectangles affects approximation accuracy.