Even though we started with a single vector, which is the position vector, we're now finding out that its derivative has to be a vector and the derivative of the derivative is also a vector.

即使我们从单个矢量出发,即位移矢量,我们现在也能得出它的导数是矢量,而且导数的导数也是一个矢量

耶鲁公开课 - 基础物理课程节选

Now, I've not given you any other example besides the displacement vector, but at the moment, we'll define a vector to be any object which looks like some multiple of i plus some multiple of j.

除了位移矢量之外,我就不再举其他的例子了,但是现在我们要定义一个矢量,可以表示为 i 的倍数加上 j 的倍数

耶鲁公开课 - 基础物理课程节选

If you are describing a particle with location R, the vector we use typically to locate a particle, R then R is just i times x + j times y, because you all know that's x and that's y.

如果你要描述一个位移为 R 的质点,这个矢量一般用表示质点 R 的位移,R 可表示为 i ? x + j ? y,显然你们都知道这段是 x,那段是 y

耶鲁公开课 - 基础物理课程节选