正六边形底面立体:平行于y轴的截面也是正六边形
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①本范例演示一个具有正六边形底面的立体,其平行于y轴的截面均为正六边形;②涉及的核心数学概念包括立体几何、多边形性质、积分计算;③作图要点——从下方『构造摘要』提炼用到了Segment(线段)、Midpoint(中点)、Intersect(交点)、Line(直线)、Sphere(球体)、Textfield(文本框)、Rotate(旋转)、Polygon(多边形)、CurveCartesian(笛卡尔曲线)、Surface(曲面)等GeoGebra命令/对象;④适合高中及以上学生学习立体几何、积分应用以及空间想象能力培养。
GeoGebra 命令及参数
Segment(H, I) → s_1Midpoint(s_1) → A_1Segment(J, K) → q_1Midpoint(q_1) → ZMidpoint(s_1) → EMidpoint(q_1) → FIntersect(upper, h, (0, 8.66025)) → BIntersect(lower, h, (0, -8.66025)) → CSegment(C, B) → qIntersect(upper, q, (0, 8.66025)) → GMidpoint(C, G) → TLine(B, D) → iSphere(B, d) → eSegment(C, B) → pTextfield(upper) → InputBox1Textfield(lower) → InputBox2Textfield(a) → InputBox3Textfield(b) → InputBox4Segment(C, G) → k_1Line(C, G) → jSphere(G, T) → kLine(T, T + (1, 0, 0)) → mRotate(G, π / 3, F_1, m) → G'Rotate(G', π / 3, F_1, Line[F_1, F_1 + (1, 0, 0)]) → G''Line(F_1, F_1 + (1, 0, 0)) → nRotate(G'', π / 3, F_1, n) → G'''Rotate(G''', π / 3, F_1, n) → G_1Polygon(C, G, G', G'', G''', G_1) → poly1, c_1, g_2, g', g'', g''', g_3Segment(G', G'') → lSegment(G'', G''') → rSegment(G''', G_1) → sSegment(G_1, C) → tSegment(G', G) → i_1Line(Z, Z + (1, 0, 0)) → fLine(D_1, D_1 + (1, 0, 0)) → gRotate(J, π / 3, D_1, g) → J'Rotate(J', π / 3, D_1, g) → J''Rotate(J'', π / 3, D_1, g) → J'''Rotate(J''', π / 3, D_1, g) → E_1Segment(J, J') → f_1Segment(J', J'') → g_1Segment(J'', J''') → j_1Segment(J''', E_1) → n_1Segment(E_1, K) → p_1Line(H_1, H_1 - (1, 0, 0)) → l_1Rotate(I, π / 3, H_1, l_1) → I'Rotate(I', π / 3, H_1, l_1) → I''Rotate(I'', π / 3, H_1, l_1) → I'''Rotate(I''', π / 3, H_1, l_1) → I_1Segment(I, I') → m_1Segment(I', I'') → r_1Segment(I'', I''') → a_1Segment(I''', I_1) → b_1Segment(I_1, H) → d_1Polygon(H, I, I', I'', I''', I_1) → poly2, h_2, i_2, i', i'', i''', i_3Polygon(K, J, J', J'', J''', E_1) → poly3, k_2, j_2, j', j'', j''', e_1CurveCartesian(t, (0.5 * (lower(t) + upper(t))) - (upper(t) - lower(t)), (((-sqrt(3))) / 2 * (lower(t) - upper(t))), t, a, b) → vCurveCartesian(t, lower(t), ((-sqrt(3)) * (lower(t) - upper(t))), t, a, b) → cCurveCartesian(t, upper(t), ((-sqrt(3)) * (lower(t) - upper(t))), t, a, b) → wCurveCartesian(t, (0.5 * (lower(t) + upper(t))) + upper(t) - lower(t), (((-sqrt(3))) / 2 * (lower(t) - upper(t))), t, a, b) → o_1Surface(u, lower(u) + ((-v) * (upper(u) - lower(u)) / 2), ((v * sqrt(3)) * (upper(u) - lower(u)) / 2), u, a, b, v, 0, 1) → oSurface(u, lower(u) - (0.5 * (upper(u) - lower(u))) + ((v * 0.5) * (upper(u) - lower(u))), (sqrt(3) / 2 * (upper(u) - lower(u))) + ((v * sqrt(3) / 2) * (upper(u) - lower(u))), u, a, b, v, 0, 1) → uSurface(u, lower(u) + (v * (upper(u) - lower(u))), (sqrt(3) * (upper(u) - lower(u))), u, a, b, v, 0, 1) → u_1Surface(u, upper(u) + (0.5 * (upper(u) - lower(u))) + (((-v) * 0.5) * (upper(u) - lower(u))), (sqrt(3) / 2 * (upper(u) - lower(u))) + ((v * sqrt(3) / 2) * (upper(u) - lower(u))), u, a, b, v, 0, 1) → v_1Surface(u, upper(u) + (v * (upper(u) - lower(u)) / 2), ((v * sqrt(3)) * (upper(u) - lower(u)) / 2), u, a, b, v, 0, 1) → w_1