二次函数图像自评
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①本范例演示了二次函数图像的绘制与变换,特别是涉及顶点、对称轴及开口方向的变化;②核心数学概念包括二次函数、顶点式(x-a)(x-b)、对称性、系数影响;③作图要点运用了Random, If, Shuffle, Coefficients, Element, Sequence, Polygon, Defined, Min, Max等GeoGebra命令与对象,用于动态生成与调整函数参数;④适合高中数学教学,用于学生自主探究二次函数图像特性与参数关系。
GeoGebra 命令及参数
Random(1, 4) → dRandom(2, 4) → e'If(d ≟ e' ∧ (count > 7 ∨ count < 5), 1, e') → eShuffle({2, 6, 7, 8}) → listshowFf2b, {8, 6, 2, 7}Shuffle({1, 4, 5, 8}) → listshowFf2a, {5, 4, 1, 8}Shuffle({1, 2, 3, 4}) → listshowFf1, {3, 4, 1, 2}If(count < 4, Element[listFf, Element[listshowFf1, 2]], If[count < 8, Element[listFf, Element[listshowFf2a, 2]], Element[listFf, Element[listshowFf2b, 2]]]) → f_{2s}Random(1, 4) → n_fCoefficients(f_{2s}) → listf_{2s}If(count < 4, Element[listFf, Element[listshowFf1, 1]], If[count < 8, Element[listFf, Element[listshowFf2a, 1]], Element[listFf, Element[listshowFf2b, 1]]]) → f_{1s}If(count < 4, Element[listFf, Element[listshowFf1, 4]], If[count < 8, Element[listFf, Element[listshowFf2a, 4]], Element[listFf, Element[listshowFf2b, 4]]]) → f_{4s}Coefficients(f_{1s}) → listf_{1s}Coefficients(f_{4s}) → listf_{4s}If(count < 4, Element[listFf, Element[listshowFf1, 3]], If[count < 8, Element[listFf, Element[listshowFf2a, 3]], Element[listFf, Element[listshowFf2b, 3]]]) → f_{3s}Coefficients(f_{3s}) → listf_{3s}Element(listCoeffs, n_f, 2) → b_fElement(listCoeffs, n_f, 1) → a_fSequence(Sequence[(x(A) + (s_p * i), y(A) + (s_p * j)), i, 0, 3], j, 0, 0) → list3CtrofGraphs, {{(5, 0), (13.8, 0), (22.6, 0), (31.400000000000002, 0)}}Polygon(E, D, F, G) → poly2, e_1, d_1, f_5, gPolygon(G, F, H, I) → poly3, g_1, f_6, h, iPolygon(J, K, L, M) → poly4, j, k, l, mPolygon(J, K, C, B) → poly5, j_1, k_1, c, b_1Sequence(Sequence[Segment[(x(A) + (s_p * i) - l_x / 2, y(A) + (s_p * j)), (x(A) + (s_p * i) + l_x / 2, y(A) + (s_p * j))], i, 0, 3], j, 0, 0) → list1Xaxes, {{7.6000000000000005, 7.600000000000001, 7.600000000000001, 7.600000000000001}}Sequence(Sequence[Segment[(x(A) + (s_p * i), y(A) + (s_p * j) - l_y / 2), (x(A) + (s_p * i), y(A) + (s_p * j) + l_y / 2)], i, 0, 3], j, 0, 0) → list2Yaxes, {{9.2, 9.2, 9.2, 9.2}}Sequence(Sequence[(x(A) + l_x / 2 + (s_p * i), y(A) + (s_p * j)), i, 0, 3], j, 0, 0) → listXarrow, {{(8.8, 0), (17.6, 0), (26.400000000000002, 0), (35.2, 0)}}Sequence(Sequence[(x(A) + (s_p * i), y(A) + l_y / 2 + (s_p * j)), i, 0, 3], j, 0, 0) → listYarrow, {{(5, 4.6), (13.8, 4.6), (22.6, 4.6), (31.400000000000002, 4.6)}}Sequence(Sequence[Text[Element[listChoicestext, i + 1], (x(A) - l_x / 2 + (s_p * (i - 1)), y(A) + l_y / 2)], i, 1, 4], j, 0, 0) → listChoicestextDisplay, {{"(a)", "(b)", "(c)", "(d)"}}Element(listCoeffs, n_f, 3) → c_fDefined(root1) → realrootsIf(count < 4, Element[listFf, Element[listshowFf1, 4]], If[count < 8, Element[listFf, Element[listshowFf2a, 4]], Element[listFf, Element[listshowFf2b, 4]]]) → f_{tests}Polygon(B, C, D, E) → poly1, b, c_1, d_2, e_2If(count < 5, Element[listshowFf1, n_f], If[count < 9, Element[listshowFf2a, n_f], Element[listshowFf2b, n_f]]) → n_sSequence(If[count < 4, Element[listshowFf1, i], If[count < 8, Element[listshowFf2a, i], Element[listshowFf2b, i]]], i, 1, 4) → listnsSequence({Cell[9, Element[listns, i]], Cell[10, Element[listns, i]]}, i, 1, 4) → listfsrootsSequence(Sequence[(((Element[listfsroots, i, j] * 2) * f_s) + x(A) + (s_p * (i - 1)), y(A)), j, 1, 2], i, 1, 4) → listfsxinttrans, {{(3.8, 0), (5.8, 0)}, {(12.600000000000001, 0), (13, 0)}, {(23.400000000000002, 0), (23.8, 0)}, {(30.6, 0), (32.6, 0)}}Min(d, e) → I1Min((-d), e) → I2Min(d, (-e)) → I3Min((-d), (-e)) → I4Min(d, e) → I5Min((-d), e) → I6Min(d, (-e)) → I7Min((-d), (-e)) → I8Max(d, e) → J1Max((-d), e) → J2Max((-d), e) → J6Max(d, (-e)) → J7Max(d, (-e)) → J3Max((-d), (-e)) → J4Max(d, e) → J5Max((-d), (-e)) → J8Element(listTurningPoints, n_f) → T_{do}Sequence(Sequence[(Element[listfsroots, i, j], y(A)), j, 1, 2], i, 1, 4) → listfsxintbeforetrans, {{(-3, 0), (2, 0)}, {(-3, 0), (-2, 0)}, {(2, 0), (3, 0)}, {(-2, 0), (3, 0)}}Element(listfsxintbeforetrans, n_f, 1) → R_{1o}Element(listfsxintbeforetrans, n_f, 2) → R_{2o}Element(listfsxinttrans, n_f, 1) → R_{1}Element(listfsxinttrans, n_f, 2) → R_{2}Element(listfYint, n_f) → Y_{into}