向量叉积的计算
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①本范例演示了三维空间中两个向量的叉积计算及其几何意义;②涉及的核心数学概念包括向量、三维空间、叉积、向量的模长与方向;③作图要点——使用了Intersect(交点)、Vector(向量)、TableText(文本表格)、Plane(平面)、Angle(角度)、Segment(线段)、LaTeX(公式)等GeoGebra命令与对象;④适合高中及以上学生学习和理解向量运算及立体几何知识。
GeoGebra 命令及参数
Intersect(xAxis, zAxis) → AVector(A, B) → uVector(A, C) → vTableText({{LaTeX["\hat{i}"], LaTeX["\hat{j}"], LaTeX["\hat{k}"]}, {LaTeX[(("\textcolor{#000099}{" * x(B)) * "}")], LaTeX[(("\textcolor{#000099}{" * y(B)) * "}")], LaTeX[(("\textcolor{#000099}{" * z(B)) * "}")]}, {LaTeX[(("\textcolor{#CC0000}{" * x(C)) * "}")], LaTeX[(("\textcolor{#CC0000}{" * y(C)) * "}")], LaTeX[(("\textcolor{#CC0000}{" * z(C)) * "}")]}}, "||c") → text2Plane(A, B, C) → aAngle(u, crossProduct) → αAngle(v, crossProduct) → βSegment((x(crossProduct), y(crossProduct), z(crossProduct)), D) → bSegment(D, F) → cSegment(D, E) → dSegment(B, G) → eSegment(H, G) → fSegment(I, G) → gSegment(C, J) → hSegment(K, J) → iSegment(L, J) → jLaTeX((((((((((((((((((((((((((((((((("\textcolor{#000099}{\vec{u}}\times\textcolor{#CC0000}{\vec{v}}\cr=\text{ }" * text2) * " \cr=\hat{i}[(\textcolor{#000099}{") * y(B)) * "})(\textcolor{#CC0000}{") * z(C)) * "})-(\textcolor{#000099}{") * z(B)) * "})(\textcolor{#CC0000}{") * y(C)) * "})] \cr\text{ }-\hat{j}[(\textcolor{#000099}{") * x(B)) * "})(\textcolor{#CC0000}{") * z(C)) * "})-(\textcolor{#000099}{") * z(B)) * "})(\textcolor{#CC0000}{") * x(C)) * "})] \cr\text{ }+\hat{k}[(\textcolor{#000099}{") * y(B)) * "})(\textcolor{#CC0000}{") * z(C)) * "})-(\textcolor{#000099}{") * z(B)) * "})(\textcolor{#CC0000}{") * y(C)) * "})] \cr=(") * x(crossProduct)) * ",") * y(crossProduct)) * ",") * z(crossProduct)) * ")")) → text3