But now there are three standard basis vectors that we typically use.

但是现在有三个标准基向量我们通常使用。

Ordinarily, the way you might think about one of a vector's coordinates tape its Z coordinate, would be to take its dot product with the 3rd standard basis factor, often called k hat.

通常 你可能会认为一个向量的坐标带它的Z坐标 就是取它与第三个标准基因子的点积 通常称为k帽。