矢量的减法

Subtracting vectors is very similar to adding vectors, with just a few small tweaks in the methodology. The easiest way to think about this algebraically is adding a negative. $\vec{A} - \vec{B} = \vec{A} + -\vec{B}$. A negative vector is essentially a positive vector in the opposite direction. For example,

This is how we would plot an arbitrary Vector A added to Vector B, aligning the tail of the second vector with the head of the first. To subtract, you only have to reverse the direction of the vector, while keeping the magnitude the same.

The vector extending from the tail of Vector A to the head of -Vector B, will be the answer to your question.

If you know how to add vectors, you practically know what I'm going to teach already. Otherwise, I'd suggest you read over the explanation on adding vectors.

So subtracting vectors is basically like adding vectors, except you subtract the coordinates of the second vector rather than adding them. So, $(3,5) - (5,1) = (-2, 4)$. Get it?