平方根与和:动态几何中的距离与方差探究
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本范例通过GeoGebra动态几何环境,演示了平方根运算与距离求和之间的数学关系,并融合了方差、反射、切线等概念。核心图形包括多个多边形、圆、线段以及由交点、中点、垂线等构造的辅助元素,通过测量距离(如EG、BC、EB)并计算其平方根或和,直观展示代数表达式与几何量之间的对应。作图要点涉及使用Point、Line、Segment、Polygon、Circle、Intersect、Distance、Midpoint、OrthogonalLine等命令,构建了包含点A、B、C、D、E、F、G、H、I、J、K以及多边形poly1、poly2、poly3的复杂结构,并利用文本对象(TextEG、TextBC等)动态显示计算结果。该范例适合高中或大学低年级学生,用于理解平方根函数的几何意义、距离公式、方差概念以及微分几何中切线与反射的直观联系,也可作为探究性学习的素材。
GeoGebra 命令及参数
Point(yAxis) → ALine(A, xAxis) → a_1Point(Circle[B, a]) → CSegment(B, C) → c_2Polygon(B, C, 4) → poly1, d, e, f, g, D, ELine(E, C) → hCircle(E, b) → kIntersect(k, h) → F, GPolygon(E, G, 4) → poly2, i, j, l, m, H, IDistance(E, G) → distanceEGDistance(B, C) → distanceBCDistance(E, B) → distanceEBPoint(Circle[J, a]) → KSegment(J, K) → pPolygon(J, K, 4) → poly3, q, r, s, t, L, MPolygon(M, K, 4) → poly4, b_1, c_1, d_1, e_1, N, ODistance(J, K) → distanceJKDistance(J, M) → distanceJMDistance(M, K) → distanceMKDistance(K, N) → distanceKNMidpoint(M, K) → PMidpoint(K, N) → QMidpoint(J, K) → RMidpoint(J, M) → SSegment(S, P) → f_1Segment(P, R) → g_1Midpoint(M, O) → TMidpoint(O, N) → USegment(T, Q) → h_1Segment(P, U) → i_1Intersect(p, q) → VIntersect(p, q) → WIntersect(p, q) → ZCircle(J, 1) → cCircle(J, 2) → k_1Intersect(c, q) → A_1,Intersect(t, poly3) → B_1, C_1Intersect(k_1, q) → D_1,Intersect(t, poly3) → E_1, F_1Intersect(k_1, t) → G_1,Intersect(c, t) → H_1,OrthogonalLine(D_1, p) → j_1OrthogonalLine(A_1, p) → l_1OrthogonalLine(H_1, t) → m_1OrthogonalLine(G_1, t) → n_1Intersect(n_1, b_1) → I_1Intersect(m_1, b_1) → J_1OrthogonalLine(J_1, b_1) → p_1OrthogonalLine(I_1, b_1) → q_1Intersect(c_1, m_1) → K_1Intersect(c_1, n_1) → L_1OrthogonalLine(K_1, c_1) → r_1OrthogonalLine(L_1, c_1) → s_1Midpoint(R, K) → M_1OrthogonalLine(M_1, p) → t_1Midpoint(S, M) → N_1OrthogonalLine(N_1, t) → a_2Intersect(e_1, t_1) → O_1OrthogonalLine(O_1, e_1) → b_2Intersect(poly3, poly4) → P_1, Q_1, R_1, S_1, T_1, U_1, V_1, W_1Intersect(b_1, a_2) → Z_1OrthogonalLine(Z_1, b_1) → d_2Intersect(d_1, d_2) → A_2Intersect(d_1, p_1) → B_2Intersect(b_2, c_1) → C_2Segment(N_1, Z_1) → e_2Segment(Z_1, A_1) → f_2Segment(H_1, J_1) → g_2Segment(J_1, M_1) → h_2Segment(J_1, B_2) → i_2Segment(Z_1, A_2) → j_2Segment(O_1, C_2) → k_2Intersect(r_1, e_1) → D_2Segment(D_2, K_1) → l_2Segment(M, O) → m_2Segment(O, N) → n_2Segment(N, K) → p_2Segment(K, M) → q_2Segment(M, J) → r_2Segment(J, K) → s_2Segment(D_1, J_1) → t_2Segment(A_1, I_1) → a_3Segment(G_1, I_1) → b_3Segment(H_1, J_1) → c_3Segment(M, K) → d_3Segment(M, J) → e_3OrthogonalLine(I_1, d_3) → f_3Segment(O, N) → h_3Segment(M, O) → i_3OrthogonalLine(L_1, p_2) → k_3Intersect(k_3, i_3) → E_2Intersect(f_3, h_3) → F_2Segment(D_2, K_1) → g_3Segment(E_2, L_1) → j_3Segment(J_1, B_2) → l_3Segment(I_1, F_2) → m_3Segment(S, P) → n_3Segment(P, R) → p_3Segment(P, U) → q_3Segment(T, Q) → r_3Circle(J, 3) → s_3Circle(J, 4) → t_3Intersect(s_3, p) → G_2,Intersect(t_3, p) → H_2,Intersect(s_3, r_2) → I_2,Intersect(t_3, r_2) → J_2,OrthogonalLine(J_2, r_2) → a_4OrthogonalLine(I_2, r_2) → b_4OrthogonalLine(I_2, r_2) → c_4OrthogonalLine(G_1, r_2) → d_4OrthogonalLine(H_1, r_2) → e_4Intersect(a_4, q_2) → K_2Intersect(a_4, p_2) → L_2Intersect(b_4, c_4) → M_2Intersect(q_2, b_4) → N_2Intersect(p_2, b_4) → O_2OrthogonalLine(N_2, n_2) → f_4OrthogonalLine(K_2, q_2) → g_4OrthogonalLine(L_2, p_2) → h_4OrthogonalLine(O_2, p_2) → i_4Intersect(m_2, h_4) → P_2Intersect(i_4, m_2) → Q_2Intersect(n_2, f_4) → R_2Intersect(g_4, n_2) → S_2Segment(D_2, K_1) → j_4Segment(E_2, L_1) → k_4Segment(Q_2, O_2) → l_4Segment(P_2, L_2) → m_4Segment(F_2, I_1) → n_4Segment(B_2, J_1) → p_4Segment(J_1, H_2) → q_4Segment(I_1, G_2) → r_4Segment(N_2, D_1) → s_4Segment(K_2, A_1) → t_4Segment(H_1, J_1) → a_5Segment(G_1, I_1) → b_5Segment(I_2, N_2) → c_5Segment(J_2, K_2) → d_5Segment(K_2, S_2) → e_5Segment(R_2, N_2) → f_5Point(q_2) → T_2Point(q_2) → U_2Point(q_2) → V_2Point(q_2) → W_2Point(q_2) → Z_2Point(r_2) → A_3Point(p) → B_3Point(q_2) → C_3Point(q_2) → D_3Point(q_2) → E_3Point(q_2) → F_3Point(r_2) → G_3Point(p) → H_3Point(q_2) → I_3Point(q_2) → J_3Point(q_2) → K_3Point(r_2) → L_3Point(p) → M_3Point(q_2) → N_3Point(q_2) → O_3Point(r_2) → P_3Point(p) → Q_3Point(q_2) → R_3Point(r_2) → S_3Point(p) → T_3