根据导数信息绘制函数草图

根据导数信息绘制函数草图
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2017-01-30 06:19
本范例演示如何利用函数的导数信息(如极值点、拐点)来手绘或构造函数的大致图像。核心数学概念包括导数、极值、拐点以及函数图像的单调性与凹凸性。作图要点:通过GeoGebra命令如FitPoly拟合多项式,Extremum和TurningPoint自动标记极值点与拐点,并使用Text、If、Segment、Point等命令辅助标注和连线;对象包括多个点(A、B、C等)、分段线段(segA至segK)以及由相邻点构造的抛物线(parABC等),最终形成基于导数信息的草图。适合高中或大学初学微积分的学生,用于理解导数与函数图像特征之间的对应关系。

GeoGebra 命令及参数

  1. Text("This function is initially:") → text8
  2. Text("f'(x) = 0 when x is:") → text4
  3. If(f'(1) < 0, "Decreasing", "Increasing") → text9
  4. Segment((1, -5), (1, 5)) → segA
  5. Segment((2, -5), (2, 5)) → segB
  6. Segment((3, -5), (3, 5)) → segC
  7. Segment((4, -5), (4, 5)) → segD
  8. Segment((5, -5), (5, 5)) → segE
  9. Segment((6, -5), (6, 5)) → segF
  10. Segment((7, -5), (7, 5)) → segG
  11. Segment((8, -5), (8, 5)) → segH
  12. Segment((9, -5), (9, 5)) → segI
  13. Segment((10, -5), (10, 5)) → segJ
  14. Segment((11, -5), (11, 5)) → segK
  15. Point(segA) → ZA
  16. Point(segB) → ZB
  17. Point(segC) → ZC
  18. Point(segD) → ZD
  19. Point(segE) → ZE
  20. Point(segF) → ZF
  21. Point(segG) → ZG
  22. Point(segH) → ZH
  23. Point(segI) → ZI
  24. Point(segJ) → ZJ
  25. Point(segK) → ZK
  26. FitPoly({ZA, ZB, ZC}, 2) → parABC
  27. FitPoly({ZB, ZC, ZD}, 2) → parBCD
  28. FitPoly({ZC, ZD, ZE}, 2) → parCDE
  29. FitPoly({ZD, ZE, ZF}, 2) → parDEF
  30. FitPoly({ZE, ZF, ZG}, 2) → parEFG
  31. FitPoly({ZF, ZG, ZH}, 2) → parFGH
  32. FitPoly({ZG, ZH, ZI}, 2) → parGHI
  33. FitPoly({ZH, ZI, ZJ}, 2) → parHIJ
  34. FitPoly({ZI, ZJ, ZK}, 2) → parIJK
  35. Text("Tick the box below to check your solution!") → text11
  36. Text("Passes through points at:") → text1
  37. Text("Drag the red points to match the graph described on the left") → text10
  38. FitPoly({A, B, C, D, E}, 4) → p
  39. Extremum(p, 1, 11) → TP_1, TP_2, TP_3
  40. Text(x(TP_1)) → stattext1
  41. TurningPoint(p) → IP_1, IP_2
  42. Text(IP_1) → inftext1
  43. Text(IP_2) → inftext2
  44. Text(x(TP_2)) → stattext2
  45. Text(x(TP_3)) → stattext3