二次方程求根公式演示
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①本范例通过动态图形演示二次方程求根公式的应用,直观展示根与系数的关系;②涉及核心数学概念包括二次方程、求根公式、判别式、函数图像;③作图要点运用了If、Intersect、Point、Vector等GeoGebra命令,构建了根的轨迹、判别式符号变化及函数图像;④适合高中数学教学,用于理解二次方程性质及求根公式的几何意义。
GeoGebra 命令及参数
If(c < 0, "-", "+") → signccIf(c ≠ 0, signcc + absc, "") → text6If(b < 0, "-", "+") → signbbIf(a < 0, "-", "") → signaIf(a ≟ 0, "", If[absa ≟ 1, signa + "x^2", a + "x^2"]) → text5If(b ≟ 0, "", If[a ≠ 0 ∧ absb ≠ 1, signbb + absb + "x", signbb + "x"]) → text7If(b < 0, "-", "") → signbIf(c < 0, "-", "") → signcIf(a < 0, "-", "+") → signaaIf(b < 0, "(" + b + ")", "" + b) → text3If(c < 0, "(" + c + ")", "" + c) → text4If(a < 0, "(" + a + ")", "" + a) → text11If(a < 0, "(" + a + ")", "" + a) → text11_1Intersect(d, xAxis) → A, BPoint(e) → CPoint(e) → D_1Vector(C, D_1) → uPoint(f) → EPoint(f) → FVector(E, F) → vIf(Disc ∈ list1, "", ("x=" * sol_3)) → text22If(Disc ∈ list1, "", "x=" + sol_4) → text23