If you want to add two vectors, you can add the arrows by the rule I gave you or just add the components of x of the two guys to get the component of the sum and likewise for the y.

如果要把两个矢量相加,你可以用我教给你们的箭头相接的方法,或者就将二者的 x 分量相加,得到和矢量的 x 分量,y 方向也是这样

耶鲁公开课 - 基础物理课程节选