你说的是向量的外积与内积吧!
从结果来说内积的结果是一个数字,外积的结果仍然是一个向量。
对于内积,它是数量积 向量A与向量B
A·B = |A| |B| cos(θ).
|A| cos(θ)是A到B的投影。
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/7aec54e736d12f2e6a6536ce4dc2d56285356838?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
或者是 在坐标系中对应的分量相乘 即是
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/8694a4c27d1ed21b2a09b64baf6eddc450da3f5f?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
而对于外积而言,它是向量积,平时我们叫它叉乘,它得到了一个垂直于原来两个向量的新向量
即是
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/95eef01f3a292df507d937bbbe315c6034a87302?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
“正确”的向量由向量空间的方向确定,即按照给定直角坐标系(i,j,k)的左右手定则.若(i,j,k)满足右手定则,则(a,b,axb)也满足右手定则;或者两者同时满足左手定则。
公式为
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/e824b899a9014c0800cfb30b087b02087af4f4ac?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)