等差数列求通项公式

GeoGebra 命令及参数

1. Random(-20, 20) → a
2. RandomElement(list1) → d
3. Polygon(A, B, C, D) → poly1, a_1, b_1, c_1, d_1
4. Polygon(E, F, G, H) → poly2, e_1, f_1, g_1, h_1
5. Polygon(I, J, K, L) → poly3, i_1, j, k, l
6. Polygon(M, N, O, P) → poly4, m, n_1, o, p
7. Polygon(Q, R, S, T) → poly5, q, r, s, t
8. Polygon(U, V, W, Z) → poly6, u_1, v, w, z_1
9. Polygon(A_1, B_1, C_1, D_1) → poly7, a_2, b_2, c_2, d_2
10. RandomElement(list2) → n
11. If(n ≟ 2, b, If[n ≟ 3, c, If[n ≟ 4, e, If[n ≟ 5, f, If[n ≟ 6, g, If[n ≟ 7, h, 0]]]]]) → u_n