坐标表示:
,
向量的模:
向量点乘:
向量叉乘:
\vec{a}\times\vec{b}=\left|\vec{a} \right|\cdot\left|\vec{b} \right|\cdot\sin<\vec{a},\vec{b}>=
\begin{vmatrix} \vec{i}& \vec{j}& \vec{k}\\x1 & y1& z1 \\ x2 & y2&z2 \end{vmatrix}=\left(y1 \cdot z2-y2 \cdot z1,x2 \cdot z1-x1 \cdot z2,x1 \cdot y2-x2 \cdot y1 \right)
方向为
http://codecogs.izyba.com/products/eqneditor/editor.php
http://www.numberempire.com/texequationeditor/equationeditor.php