圆柱体展开 by Мілочкіна Лілія
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①这个范例演示了圆柱体的展开过程,直观展示侧面如何转化为矩形;②涉及核心数学概念包括圆柱体表面积计算、侧面展开图、矩形面积公式、几何变换;③作图要点运用了Cylinder(圆柱体)、Line(线)、Intersect(交点)、Plane(平面)、Rotate(旋转)、Dilate(缩放)、Vector(向量)、Translate(平移)、Polygon(多边形)、Segment(线段)、CircleArc(圆弧)、Angle(角度)、CurveCartesian(笛卡尔曲线)、Surface(曲面)、Midpoint(中点)、Mirror(镜像)等GeoGebra命令和对象;④适合高中阶段学生理解圆柱体表面积计算方法,也可用于立体几何教学。
GeoGebra 命令及参数
Cylinder(A, C, r) → a, c, d, bLine(D, E) → fIntersect(f, d, 1) → FSphere(F, r) → eIntersect(f, e) → G, HPlane(G, F, C) → gRotate(C, If[0 < i ≤ 1, (i * pi / 2), pi / 2], D, g) → C'Rotate(d, If[0 < i ≤ 1, (i * pi / 2), pi / 2], D, g) → d'Rotate(dd, If[0 < i ≤ 1, (i * pi / 2), pi / 2], D, g) → dd'Dilate(C, If[1 < i ≤ 2, 2 - i, 0], I) → C'_1Dilate(C, If[1 < i ≤ 2, 2 - i, 0], J) → C'_2Vector(C, C'_1) → uVector(C, C'_2) → vTranslate(dd, u) → dd'_1Translate(dd, v) → dd'_2Translate(K, u) → K'Translate(K, v) → K'_1Rotate(K', If[1 < i ≤ 2, ((i - 1) * pi), pi], C'_1) → K''Rotate(K'_1, If[1 < i ≤ 2, ((-(i - 1)) * pi), (-pi)], C'_2) → LTranslate(D, u) → D'Translate(D, v) → D'_1Polygon(D', D'_1, N, M) → poly1, d'_1, d'_2, n, mSegment(K'', Q) → jCircleArc(P, Q, M) → kSegment(L, S) → lCircleArc(R, N, S) → pCircleArc(C'_2, D'_1, L) → qCircleArc(C'_1, K'', D') → sPlane(T, A, B) → oRotate(C', If[2 < i ≤ 3, ((i - 2) * pi / 2), pi / 2], E, g) → C''Rotate(poly1, If[2 < i ≤ 3, ((i - 2) * pi / 2), pi / 2], E, g) → poly1'Rotate(d', If[2 < i ≤ 3, ((i - 2) * pi / 2), pi / 2], E, g) → d'_3Rotate(dd', If[2 < i ≤ 3, ((i - 2) * pi / 2), pi / 2], E, g) → dd'_3Rotate(K'', If[2 < i ≤ 3, ((i - 2) * pi / 2), pi / 2], E, g) → K'''Rotate(Q, If[2 < i ≤ 3, ((i - 2) * pi / 2), pi / 2], E, g) → Q'Segment(K''', Q') → j'Rotate(L, If[2 < i ≤ 3, ((i - 2) * pi / 2), pi / 2], E, g) → L'Rotate(S, If[2 < i ≤ 3, ((i - 2) * pi / 2), pi / 2], E, g) → S'Segment(L', S') → l'Dilate(C'', If[3 < i ≤ 4, 4 - i, 0], U) → C'''Vector(C'', C''') → wDilate(C'', If[3 < i ≤ 4, 4 - i, 0], V) → C'''_1Vector(C'', C'''_1) → tTranslate(Z, w) → Z'Translate(Z, t) → Z'_1Translate(W, w) → W'Translate(W, t) → W'_1Rotate(W', If[3 < i ≤ 4, ((-(i - 3)) * pi), (-pi)], C''') → W''CircleArc(C''', Z', W'') → c_1Segment(Z, Z') → f_1Rotate(W'_1, If[3 < i ≤ 4, ((i - 3) * pi), pi], C'''_1) → A_1CircleArc(C'''_1, Z'_1, A_1) → d_1Segment(Z, Z'_1) → g_1Segment(R, N) → h_1Angle(N, R, S) → αCurveCartesian(x(C'_2) + (r * cos(t)), y(C'_2) + (r * sin(t)), z(C'_2), t, pi / 2, pi / 2 + α) → a_1Vector(A, C) → ttSurface(x(C'_2) + (r * cos(t)) - (u * x(tt)), y(C'_2) + (r * sin(t)) - (u * y(tt)), z(C'_2) - (u * z(tt)), u, 0, 1, t, pi / 2, pi / 2 + α) → b_1Surface((-x(C'_2)) - (r * cos(t)) - (u * x(tt)), y(C'_2) + (r * sin(t)) - (u * y(tt)), z(C'_2) - (u * z(tt)), u, 0, 1, t, pi / 2, pi / 2 + α) → e_1Midpoint(L', S') → B_1Midpoint(K''', Q') → C_1Line(B_1, C_1) → i_1Mirror(d_1, i_1) → k_1Mirror(c_1, i_1) → p_1Mirror(Z, i_1) → Z'_2Mirror(Z', i_1) → Z''Segment(Z'_2, Z'') → j_1Mirror(Z, i_1) → Z'_3Mirror(Z'_1, i_1) → D_1Segment(Z'_3, D_1) → l_1