向量基本概念

1基向量--
长度为一个单位长度的向量

Every vector a in three dimensions is a linear combination of the standard basis vectors i, j, and k.

2向量叉积--

方向根据右手法则确定，就是手掌立在a、b所在平面的向量a上，掌心由a转向b的过程中，大拇指的方向就是叉积的方向。

The cross product is defined by the formula

推到公式：

The standard basis vectors i, j, and k satisfy the following equalities in a right hand coordinate system。

         角度大于90 ===》     角度为0===》

 

   

 

meaning that the three scalar components of the resulting vector s = s₁i + s₂j + s₃k = u × v are

Using column vectors, we can represent the same result as follows:

The cross product can also be expressed as the formal^{[note 1]} determinant: