Secant and Tangent Lines on Parabola 2

① This interactive example dynamically shows how a secant line on a parabola approaches the tangent line as two points move closer, illustrating the geometric transition between them. ② Core mathematical concepts include quadratic functions, secant slope, tangent slope, and the geometric meaning of the derivative, where the secant slope tends to the derivative value at the tangency point. ③ Construction details: using GeoGebra commands Point to place two movable points on the parabola, Line to draw the secant through them, Slope to display the secant's slope, Tangent to generate the tangent at a fixed point, and text objects (text1, text2, text3) to label slope values and explanations; objects include a, b, c, d, Point, B, e, m, f, n. ④ Suitable for high school or early college students learning calculus, particularly for understanding the definition of the derivative and tangent lines, and useful as a classroom demonstration tool.