数轴上表示不等式

数轴上表示不等式
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2015-07-02 17:14
①本范例演示如何在数轴上表示不等式;②涉及的核心数学概念包括不等式、数轴表示法;③作图要点:使用了Textfield, Segment, Remove, If, IndexOf, Sequence, Denominator等GeoGebra命令和对象;④适合初中及以上学生学习和理解不等式的基本表示方法。

GeoGebra 命令及参数

  1. Textfield(a) → Inequality
  2. Segment((x(P_{arrowright}), s_n), (x(Corner[2]), s_n)) → xAxis_{continuation}
  3. Textfield(xLeft) → InputBox1
  4. Textfield(xRight) → InputBox2
  5. Remove({IndexOf[8804, TextToUnicode[Text[a]]], IndexOf[62, TextToUnicode[Text[a]]], IndexOf[8805, TextToUnicode[Text[a]]], IndexOf[60, TextToUnicode[Text[a]]]}, {NaN, NaN, NaN}) → l1
  6. If(Min[a] < -100000, Max[a], Min[a]) → ineqnumpivot
  7. IndexOf(3, listidentifyIneq) → numidentifyIneq
  8. If(numidentifyIneq ≟ 2 ∨ numidentifyIneq ≟ 4, Midpoint[(x(Corner[2]), 1), (ineqnumpivot, 1)], Midpoint[(x(Corner[1]), 1), (ineqnumpivot, 1)]) → P_{ineqtext}
  9. Sequence(Text[LaTeX[i], (i - ticksize / 5 + n_t, -1.8 + s_n)], i, xLeft + 1, xRight - 1, ticksize) → ListxaxisNumbers
  10. Denominator(ineqnumpivot) → denompivot
  11. Sequence((i, s_n), i, xLeft, xRight, 1 / denompivot) → listTicks