The funeral of Y.S Rajasekhara Reddy will be attended by Congress Party boss, Sonia Gandhi and Prime Minister Manmohan Singh.

VOA: standard.2009.09.03

Once you do that, I think it's fairly clear that it has got a y component that's given by cosine the x component is negative.

用了这个结论,我想很明显,y 分量由 cos φ 给出,它的 x 分量是负的

耶鲁公开课 - 基础物理课程节选

At every instant, it's got a location given by the vector R; R itself is contained in a pair of numbers, x and y, and they vary with time.

在每一个瞬时,它的位置由位矢 R 给出,R 本身包含了一对坐标值 x 和 y,并且它们都随着时间的变化而变化

耶鲁公开课 - 基础物理课程节选