And, we look at how the position vector changes.

来看看位置矢量的改变。

youdao

So, it's the second derivative of a position vector.

它是位置向量的二阶导。

youdao

Well, I claim that the position vector is in the plane.

我断言，这个位置矢量在平面上。

youdao

Well, I claim that the position vector is in the plane.

我断言，这个位置矢量在平面上。

youdao