二元函数极值演示
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①本范例演示二元函数的极值点及其几何意义;②涉及核心数学概念包括偏导数、海森矩阵、函数极值判定;③构造要点:使用Derivative计算偏导数,IntersectPath求交点,Vector绘制向量,OrthogonalPlane创建法平面,Length测量距离等;④适合大学数学、微积分课程教学与学习。
GeoGebra 命令及参数
Derivative(f, x) → f_xDerivative(f_x, y) → f_{xy}Derivative(f_x, x) → f_{xx}Derivative(f, y) → f_yDerivative(f_y, y) → f_{yy}IntersectPath(g, f_x) → ndxIntersectPath(g, f_y) → ndyDerivative(f_y, x) → f_{yx}Textfield(f) → CasillaDeEntrada1Vector(((-f_x(P_1)), (-f_y(P_1)), 1) / sqrt(1 + f_x(P_1)^(2) + f_y(P_1)^(2))) → uVector(P_1, P_1 + u) → u'OrthogonalPlane(P_1, u') → aIntersectPath(a, f) → bTextfield(P) → CasillaDeEntrada2Length(lPc) → nJoin({{{"(x, y)", "f(x,y)", "f_x(x,y)", "f_y(x,y)", "f_{xx}(x,y)", "H(x,y)", "Tipo"}}, Sequence[{lPc(k), f(lPc(k)), f_x(lPc(k)), f_y(lPc(k)), f_{xx}(lPc(k)), H(lPc(k)), If[f_x(lPc(k)) ≠ 0 ∨ f_y(lPc(k)) ≠ 0, "No crítico", f_{xx}(lPc(k)) > 0 ∧ H(lPc(k)) > 0, "Mínimo relativo", f_{xx}(lPc(k)) < 0 ∧ H(lPc(k)) > 0, "Máximo relativo", H(lPc(k)) ≠ 0, "Punto de silla", "??"]}, k, 1, Length[lPc]]}) → tPcTableText(tPc, "|_") → texto2Sequence((x(lPc(k)), y(lPc(k)), f(lPc(k))), k, 1, n) → lPczSequence({lPc(k), f_x(lPc(k)), f_y(lPc(k)), f_{xx}(lPc(k)), H(lPc(k)), If[f_x(lPc(k)) ≠ 0 ∨ f_y(lPc(k)) ≠ 0, "No crítico", f_{xx}(lPc(k)) > 0 ∧ H(lPc(k)) > 0, "Mínimo relativo", f_{xx}(lPc(k)) < 0 ∧ H(lPc(k)) > 0, "Máximo relativo", H(lPc(k)) ≠ 0, "Punto de silla", "??"]}, k, 1, Length[lPc]) → lPc0