利用单位圆比较相位平移后的三角函数:cos(π/2+x)、sin(π/2+x)与cos(π+x)、sin(π+x)对照sin x、cos x

利用单位圆比较相位平移后的三角函数:cos(π/2+x)、sin(π/2+x)与cos(π+x)、sin(π+x)对照sin x、cos x
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2021-01-15 04:11
本范例在单位圆与坐标几何语境中,演示把角度分别平移到 π/2+x 与 π+x 后,余弦与正弦的值如何与基准角 x 的 sinx、cosx 建立对应关系。核心数学概念包括单位圆上的角度—坐标映射、三角函数的相位变换(π/2 与 π 的平移规律)、以及符号变化与对称性。作图要点:通过 Intersect、Circle、Point、Line 与 Angle 定义单位圆、角与相关射线/直线;用 OrthogonalLine、Midpoint、Segment 等确定投影与连线位置;结合 Rotate、RotateText、Translate、Mirror 等完成相位对应的旋转/镜像与标注;再用 Vector、CircleArc、CircleSector、Ray 与 Polygon 辅助刻画扇形、弧段与可比的几何结构。对象方面涉及多个点/向量/弧段的构造(如若干已命名点与角度标记)以形成可视对比。适合中学高年级与大学基础数学入门,用于三角函数性质复习、动态几何理解与课堂演示。

GeoGebra 命令及参数

  1. Intersect(xAxis, yAxis) → O
  2. Circle(O, 1) → c
  3. Intersect(c, xAxis) → C_1, D
  4. Segment(C_1, D) → r
  5. Point(r) → I_1
  6. Rotate(D, j, O) → M
  7. If(j < 0, M) → M1
  8. Intersect(c, yAxis) → K, L
  9. Line(K, L) → s
  10. OrthogonalLine(M, yAxis) → a
  11. Intersect(a, yAxis) → S
  12. Angle(D, O, M) → β
  13. OrthogonalLine(M, xAxis) → b
  14. Intersect(b, xAxis) → C
  15. Segment(O, S) → d
  16. Segment(O, C) → e
  17. Segment(M, S) → g
  18. Segment(M, C) → h
  19. Midpoint(M, S) → G
  20. Midpoint(M, C) → H
  21. Vector(M, G) → u
  22. Vector(M, H) → v
  23. Rotate(D, 0.52, O) → I
  24. Angle(I, O, D) → γ
  25. Rotate(D, 1.0471975511965976, O) → J
  26. Angle(D, O, J) → δ
  27. Mirror(J, yAxis) → M_1
  28. Mirror(I, yAxis) → N
  29. Mirror(M_1, xAxis) → O_2
  30. Mirror(J, xAxis) → P
  31. Mirror(I, xAxis) → Q
  32. Mirror(Q, yAxis) → R
  33. Rotate(D, 0.7853981633974483, O) → T
  34. Angle(D, O, T) → ε
  35. Mirror(T, yAxis) → U
  36. Mirror(T, xAxis) → V
  37. Mirror(U, xAxis) → W
  38. If(Distance[M, K] < 0.1, F) → s_4
  39. Segment(R, I) → i
  40. Segment(T, W) → k
  41. Segment(J, O_2) → l
  42. Segment(Q, N) → m
  43. Segment(P, M_1) → p
  44. Segment(L, K) → q
  45. Line(C_1, D) → t
  46. Segment(O, M) → b_1
  47. Point(t) → Z
  48. Point(t) → E_1
  49. Point(s) → C_2
  50. Point(s) → D_2
  51. Point(s) → E_2
  52. Point(s) → F_2
  53. Segment(U, V) → c_1
  54. Point(c) → B
  55. CircleArc(O, M1, D) → k_1
  56. If(j > 0, M) → M2
  57. CircleArc(O, D, M2) → k_2
  58. Angle(I_1, O, M2) → α
  59. Angle(M1, O, I_1) → ζ
  60. Segment(J, O) → f
  61. Segment(T, O) → a1
  62. Segment(I, O) → b1
  63. Segment(U, O) → a_1
  64. Segment(O, W) → d_1
  65. Segment(O, V) → e_1
  66. Intersect(c, d_1, 1) → A
  67. Intersect(c, d_1, 1) → E
  68. CircleArc(F_1, G_1, H_1) → f_1
  69. Point(f_1) → J_1
  70. Point(f_1) → K_1
  71. Vector(K_1, J_1) → w
  72. FractionText(dir) → texte3
  73. Segment(M_1, P) → g_1
  74. Segment(R, I) → h_1
  75. Segment(J, O_2) → i_1
  76. Segment(D, B_1) → j_1
  77. Point(j_1) → L_1
  78. Polygon(B_1, D_1, L_1) → t1, l_1, m_1, n_1
  79. FractionText(mesp) → texte4
  80. FractionText(mesp) → texte5
  81. Point(c) → R_1
  82. Segment(N, Q) → m_2
  83. Rotate(R_1, (-(60°)), O) → W_1
  84. Segment(O, W_1) → n_2
  85. OrthogonalLine(R_1, n_2) → p_2
  86. Intersect(p_2, n_2) → Z_1
  87. Circle(O, 1.25) → c_2
  88. Circle(O, 1) → d_2
  89. Sequence(Rotate[M + (0.35, 0), i°, O], i, 0, 360, 1) → l1
  90. Circle(O, 1.25) → s_2
  91. Sequence(Text[i + "°", Element[l1, i] - (0.065, 0.015)], i, 0, 360, 10) → l2
  92. Circle(O, 1.45) → e_2
  93. Circle(O, 1.45) → t_2
  94. Sequence(Rotate[M + (0.25, 0), i°, O], i, 0, 360, 5) → l3
  95. CircleSector(O, K, C_1) → c_3
  96. CircleSector(O, C_1, L) → d_3
  97. CircleSector(O, L, D) → e_3
  98. Circle(O, 0.15) → f_3
  99. Rotate(B_3, 60°, A_3) → C_3
  100. Ray(A_3, C_3) → n_3
  101. Segment(A_3, B_3) → p_3
  102. OrthogonalLine(B_3, p_3) → q_3
  103. Intersect(q_3, n_3) → K_3
  104. Midpoint(J, O) → M_3
  105. Midpoint(O, U) → N_3
  106. Midpoint(O, W) → O_3
  107. Midpoint(O, V) → P_3
  108. Segment(D, D + (0.45, 0)) → a_2
  109. OrthogonalLine(R_1, r) → p_1
  110. Intersect(p_1, r) → P_1
  111. Polygon(R_1, O, P_1) → t2, q_1, r_1, o
  112. Angle(Q_1, A_3, S_1) → η
  113. Polygon(S_1, Q_1, A_3) → t3, a_3, s_1, t_1
  114. Angle(R_1, P_1, O) → θ
  115. Angle(P_1, O, R_1) → ι
  116. Rotate(R_1, o_1, O) → T_1
  117. Rotate(P_1, o_1, O) → U_1
  118. Polygon(O, T_1, U_1) → t4, u_1, o_2, f_2
  119. Angle(T_1, U_1, O) → κ
  120. Translate(T_1, Vector[O, If[o_1 ≟ π / 2, V_1, K_2]]) → I_2
  121. Translate(U_1, Vector[O, If[o_1 ≟ π / 2, V_1, K_2]]) → J_2
  122. Translate(O, Vector[O, If[o_1 ≟ π / 2, V_1, K_2]]) → O'
  123. Polygon(O', I_2, J_2) → t4', j_2, o', i_2
  124. Angle(U_1, O, T_1) → λ
  125. Angle(P_1, O, U_1) → μ
  126. Angle(S_1, Q_1, A_3) → ν
  127. Angle(I_2, J_2, If[o_1 ≟ π / 2, V_1, K_2]) → ξ
  128. Point(i_2) → N_2
  129. Point(s_1) → P_2
  130. Point(a_3) → Q_2
  131. Point(o') → R_2
  132. RotateText(texte26, 90°) → texte27
  133. RotateText(texte29, 90°) → texte30
  134. Midpoint(s_1) → S_2

AI 绘图提示语参考

在单位圆上展示角度平移 π/2+x 和 π+x 对余弦和正弦值的影响,并可视化这些变换后的函数值如何对应于基准函数 sin x 和 cos x。首先绘制单位圆和坐标轴,然后标出关键角度和射线,通过正交投影和连接点表示函数值。使用旋转、平移和镜像操作来展示相位变换,并用向量、圆弧和扇形突出几何元素,最后用线段和点连接所有元素以清晰展示比较关系。
以上提示语为根据原始绘图命令整理而来,仅供参考。