可修改固体:平行于y轴的正八边形截面
几何画板及绘图内容加载中,请稍等……
这个范例演示了一个可修改固体,其平行于y轴的截面是正八边形。涉及的核心数学概念包括立体几何、解析几何和微积分。作图要点使用了GeoGebra的Segment、Midpoint、Intersect、Line、Textfield、Rotate、Polygon、Surface、CurveCartesian等命令和对象。适合高中及以上学生学习和理解复杂几何体体积计算和截面分析。
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, (-10, 10.876772823989416)) → BIntersect(lower, h, (-10, -2.0796594266992683)) → CSegment(C, B) → qIntersect(upper, q, (-9.999999999999998, 10.876772823989416)) → GMidpoint(C, G) → TLine(B, D) → iSegment(C, B) → pTextfield(upper) → InputBox1Textfield(lower) → InputBox2Textfield(a) → InputBox3Textfield(b) → InputBox4Segment(C, G) → k_1Line(C, G) → jLine(T, T + (1, 0, 0)) → mRotate(G, pi / 3, F_1, m) → G'Rotate(G', pi / 3, F_1, Line[F_1, F_1 + (1, 0, 0)]) → G''Line(F_1, F_1 + (1, 0, 0)) → nRotate(G'', pi / 3, F_1, n) → G'''Rotate(G''', pi / 3, F_1, n) → G_1Line(Z, Z + (1, 0, 0)) → fLine(D_1, D_1 + (1, 0, 0)) → gLine(H_1, H_1 - (1, 0, 0)) → l_1Rotate(I, pi / 3, H_1, l_1) → I'Rotate(I', pi / 3, H_1, l_1) → I''Rotate(I'', pi / 3, H_1, l_1) → I'''Rotate(I''', pi / 3, H_1, l_1) → I_1Line(E_1, E_1 + (1, 0, 0)) → lRotate(G, pi / 4, E_1, l) → G'_1Rotate(G'_1, pi / 4, E_1, l) → J_1Rotate(J_1, pi / 4, E_1, l) → K_1Rotate(K_1, pi / 4, E_1, l) → L_1Rotate(L_1, pi / 4, E_1, l) → M_1Rotate(M_1, pi / 4, E_1, l) → N_1Polygon(G, G'_1, J_1, K_1, L_1, M_1, N_1, C) → poly3, g_1, g'_1, j_1, k_2, l_2, m_1, n_1, cSegment(G'_1, J_1) → rSegment(J_1, K_1) → sSegment(K_1, L_1) → tSegment(L_1, M_1) → f_1Segment(M_1, N_1) → i_1Segment(N_1, C) → p_1Segment(G, G'_1) → r_1Rotate(J, pi / 4, Line[O_1, O_1 + (1, 0, 0)]) → J'Rotate(J', pi / 4, Line[O_1, O_1 + (1, 0, 0)]) → J''Rotate(J'', pi / 4, Line[O_1, O_1 + (1, 0, 0)]) → J'''Rotate(J''', pi / 4, Line[O_1, O_1 + (1, 0, 0)]) → P_1Rotate(P_1, pi / 4, Line[O_1, O_1 + (1, 0, 0)]) → Q_1Rotate(Q_1, pi / 4, Line[O_1, O_1 + (1, 0, 0)]) → R_1Polygon(K, J, J', J'', J''', P_1, Q_1, R_1) → poly4, k_3, j_2, j', j'', j''', p_2, q_2, r_2Segment(J, J') → a_1Segment(J', J'') → b_1Segment(J'', J''') → d_1Segment(J''', P_1) → e_1Segment(P_1, Q_1) → f_2Segment(Q_1, R_1) → m_2Segment(R_1, K) → n_2Rotate(H, pi / 4, Line[S_1, S_1 + (1, 0, 0)]) → H'Rotate(H', pi / 4, Line[S_1, S_1 + (1, 0, 0)]) → H''Rotate(H'', pi / 4, Line[S_1, S_1 + (1, 0, 0)]) → H'''Rotate(H''', pi / 4, Line[S_1, S_1 + (1, 0, 0)]) → T_1Rotate(T_1, pi / 4, Line[S_1, S_1 + (1, 0, 0)]) → U_1Rotate(U_1, pi / 4, Line[S_1, S_1 + (1, 0, 0)]) → V_1Polygon(H, I, V_1, U_1, T_1, H''', H'', H') → poly5, h_3, i_4, v_2, u_2, t_2, h''', h'', h'Segment(I, V_1) → s_2Segment(V_1, U_1) → a_2Segment(U_1, T_1) → b_2Segment(T_1, H''') → c_2Segment(H''', H'') → d_2Segment(H'', H') → e_2Segment(H', H) → f_3Surface(u, lower(u) - (v * (upper(u) - lower(u)) / sqrt(2)), (v * (upper(u) - lower(u)) / sqrt(2)), u, a, b, v, 0, 1) → vCurveCartesian(t, lower(t) - (upper(t) - lower(t)) / sqrt(2), (upper(t) - lower(t)) / sqrt(2), t, a, b) → oCurveCartesian(t, lower(t) - (upper(t) - lower(t)) / sqrt(2), (upper(t) - lower(t)) / sqrt(2) + upper(t) - lower(t), t, a, b) → uCurveCartesian(t, lower(t), (2 * (upper(t) - lower(t)) / sqrt(2)) + upper(t) - lower(t), t, a, b) → wCurveCartesian(t, upper(t), (2 * (upper(t) - lower(t)) / sqrt(2)) + upper(t) - lower(t), t, a, b) → o_1CurveCartesian(t, upper(t) + (upper(t) - lower(t)) / sqrt(2), (upper(t) - lower(t)) / sqrt(2) + upper(t) - lower(t), t, a, b) → u_1CurveCartesian(t, upper(t) + (upper(t) - lower(t)) / sqrt(2), (upper(t) - lower(t)) / sqrt(2), t, a, b) → v_1Surface(u, upper(u) + (v * (upper(u) - lower(u)) / sqrt(2)), (v * (upper(u) - lower(u)) / sqrt(2)), u, a, b, v, 0, 1) → w_1Surface(u, lower(u) - (upper(u) - lower(u)) / sqrt(2), (v * (upper(u) - lower(u))) + (upper(u) - lower(u)) / sqrt(2), u, a, b, v, 0, 1) → o_2Surface(u, lower(u) - (upper(u) - lower(u)) / sqrt(2) + (v * (upper(u) - lower(u)) / sqrt(2)), upper(u) - lower(u) + (upper(u) - lower(u)) / sqrt(2) + ((v * (upper(u) - lower(u)))) / sqrt(2), u, a, b, v, 0, 1) → w_2Surface(u, upper(u) + (upper(u) - lower(u)) / sqrt(2), (v * (upper(u) - lower(u))) + (upper(u) - lower(u)) / sqrt(2), u, a, b, v, 0, 1) → a_3Surface(u, lower(u) + (v * (upper(u) - lower(u))), upper(u) - lower(u) + (upper(u) - lower(u)) / sqrt(2) + (upper(u) - lower(u)) / sqrt(2), u, a, b, v, 0, 1) → b_3Surface(u, upper(u) + (v * (upper(u) - lower(u)) / sqrt(2)), ((1 + sqrt(2)) * (upper(u) - lower(u))) - (v * (upper(u) - lower(u)) / sqrt(2)), u, a, b, v, 0, 1) → c_3