一阶线性齐次微分方程的相图
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①本范例演示了一阶线性齐次微分方程的相图;②涉及的核心数学概念包括微分方程、线性方程、对数函数、相似三角形、频率分布、直角三角形;③作图要点提炼自构造摘要,使用了Identity, Element, If, Textfield, UnitVector, Line, SurdText, Locus, Sequence, Point, Segment, Mirror, Determinant, LaTeX等GeoGebra命令/对象;④适合大学数学专业学生或对微分方程图形化理解有需求的学习者。
GeoGebra 命令及参数
Identity(2) → IElement(eigenvalues, 2) → λ2Element(eigenvalues, 1) → λ1If(c ≠ 0 ∨ a - λ1 ≠ 0, Vector[((sgn(a - λ1) * (a - λ1)), (sgn(a - λ1) * c))], Vector[If[b ≠ 0 ∨ d - λ1 ≠ 0, Vector[((sgn(b) * b), (sgn(b) * (d - λ1)))], Vector[(1, 0)]]]) → Ev2If(c ≟ 0 ∧ b ≟ 0 ∧ a > d, Vector[(1, 0)], Vector[If[c ≟ 0 ∧ b ≟ 0 ∧ a ≤ d, Vector[(1, 0)]]]) → w2If(c ≟ 0 ∧ b ≟ 0 ∧ a > d, Vector[(0, 1)], Vector[If[c ≟ 0 ∧ b ≟ 0 ∧ a ≤ d, Vector[(0, 1)]]]) → w1Textfield(a) → InputBox1Textfield(b) → InputBox2Textfield(c) → InputBox3Textfield(d) → InputBox4If(a^(2) + ((4 * b) * c) - ((2 * a) * d) + d^(2) > 0, 2, If[a^(2) + ((4 * b) * c) - ((2 * a) * d) + d^(2) < 0, 0, 1]) → numEigenvaluesUnitVector(Vector[If[eive2 ≟ eive2, eive2, Vector[If[w2 ≟ w2, w2, Ev2]]]]) → e2UnitVector(Vector[If[eive1 ≟ eive1, eive1, Vector[If[numEigenvalues ≟ 1, Ev2, Vector[If[w1 ≟ w1, w1, Ev1]]]]]]) → e1Line((0, 0), e1) → hLine((0, 0), e2) → iSurdText(x(e1)) → text8SurdText(y(e1)) → text9SurdText(x(e2)) → text10SurdText(y(e2)) → text11SurdText(λ1) → text14SurdText(λ2) → text15Locus(g(x, y) / f(x, y), A) → numericalIntegral1Sequence((x(Element[ListP, i]) + (0.001 * f(x(Element[ListP, i]), y(Element[ListP, i]))), y(Element[ListP, i]) + (0.001 * g(x(Element[ListP, i]), y(Element[ListP, i])))), i, 1, 8) → ListP1Sequence(Segment[Element[ListP, i], Element[ListP1, i]], i, 1, 8) → SegmentListElement(SegmentList, 1) → Segment1Element(SegmentList, 2) → Segment2Element(SegmentList, 3) → Segment3Element(SegmentList, 4) → Segment4Element(SegmentList, 5) → Segment5Element(SegmentList, 6) → Segment6Element(SegmentList, 7) → Segment7Sequence(Locus[g(x, y) / f(x, y), Element[ListP, i]], i, 1, 8) → list1Element(SegmentList, 8) → Segment8Point(h) → NPoint(i) → OSegment(N, N1) → Segment9Segment(O, O1) → Segment10Mirror(N, (0, 0)) → N'Mirror(N1, (0, 0)) → N1'Segment(N', N1') → Segment9'Mirror(O, (0, 0)) → O'Mirror(O1, (0, 0)) → O1'Segment(O', O1') → Segment10'Determinant(T) → DeterminantTextfield(a) → InputBox1_1Textfield(b) → InputBox2_1Textfield(c) → InputBox3_1Textfield(d) → InputBox4_1Determinant(T_1) → Determinant_1If(eive2 ≟ eive2, eive2, Vector[If[w2 ≟ w2, w2, Ev2]]) → e22If(eive1 ≟ eive1, eive1, Vector[If[numEigenvalues ≟ 1, Ev2, Vector[If[w1 ≟ w1, w1, Ev1]]]]) → e11Element(CEigenvalues, 1) → cλ1Element(CEigenvalues, 2) → cλ2Identity(2) → I_1Element(eigenvalues_1, 1) → λ1_1Textfield(a) → InputBox1_2Textfield(b) → InputBox2_2Textfield(c) → InputBox3_2Textfield(d) → InputBox4_2SurdText(λ1_1) → text14_1Determinant(T_2) → Determinant_2Textfield(a) → InputBox1_3Textfield(b) → InputBox2_3Textfield(c) → InputBox3_3Textfield(d) → InputBox4_3LaTeX(CEigenvalues) → text16