圆锥曲线分类:一般情况
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①本范例演示了通过旋转变换和平移变换对二次曲线进行分类的过程;②涉及的核心数学概念包括旋转变换、平移变换、二次曲线方程、矩阵运算;③作图要点:使用了 Rotate, Translate, Matrix, Eigenvec1fixed, Eigenvec2fixed 等GeoGebra命令和对象来构建和变换图形;④适合高中及以上数学学习者,用于理解圆锥曲线的几何性质和变换方法。
GeoGebra 命令及参数
If(a ≟ c, π / 4, (1 / 2 * atan(b / (a - c)))) → thetaRotate(e_1, theta) → Eigenvec1fixedRotate(e_2, theta) → Eigenvec2fixedTranspose(P) → PTVertex(g) → Vertex2, D, E, FCenter(g) → CVertex(conic) → Vertex, G, H, ICenter(conic) → BRotate(e_2, (Signo * θ)) → Eigenvec2Textfield(a) → InputBox1Textfield(b) → InputBox2Textfield(c) → InputBox3Textfield(d) → InputBox4Textfield(e) → InputBox5Textfield(f) → InputBox6If((a - c)^(2) + (2 * b^(2)) > 0, 2, If[(a - c)^(2) + (2 * b^(2)) < 0, 0, 1]) → numEigenvaluesVector(If[C ≟ C, C, Vertex2], (0, 0)) → vectorauxiliar01Translate(g, vectorauxiliar01) → g'Coefficients(g') → coefficientsVector((0, 0), If[B ≟ B, B, Vertex]) → vectorauxiliar02Rotate(e_1, (Signo * θ)) → Eigenvec1Line((0, 0), Eigenvec1) → uaxisLine((0, 0), Eigenvec2) → vaxisTranslate(uaxis, Vector[(t * vectorauxiliar02)]) → uaxis'Translate(vaxis, Vector[(t * vectorauxiliar02)]) → vaxis'Center(conic) → CentreCenter(g) → Centre2Determinant(A) → DetADeterminant(AQ) → DetAQDeterminant(P) → DetPLaTeX($5) → text1Text(text1, If[Δ_2 ≟ 0, Vertex + 0.5, B + 0.5], true, true) → text5If(sgn(theta) ≟ -1, abs(α), abs(α)) → limitthetaElement(PTAP, 1, 1) → TestEigen1Element(PTAP, 2, 2) → TestEigen2