QR4-02-CYU4 (Sketching stretches of parabolas)

① This interactive example demonstrates how to sketch vertical or horizontal stretches of parabolas by adjusting the quadratic function's parameters, with immediate feedback on correctness. ② Core math concepts include quadratic functions, vertex form, stretching transformations (effect of coefficient on opening direction and width), and the relationship between algebraic expressions and graphs. ③ Construction details: from the summary, the example uses Polygon to create answer regions, PointIn to detect clicks, Element and FitPoly to generate and verify polynomial equations, and LaTeX for displaying formulas; objects include questionList, points A1-A5, auxiliary objects D1-D5, and control buttons like Initialize and TryAnother, enabling dynamic question generation and instant scoring. ④ Suitable for high school students learning transformations of quadratic functions, and useful for classroom demonstrations or self-paced practice to reinforce understanding of how parameters affect parabola shape.