Edexcel IGCSE Maths 复习笔记 5.1.2 Vectors - Finding Paths
Finding paths in vector diagrams
- It is important to be able to describe vectors by following paths through a geometric diagram
- The following grid is made up entirely of parallelograms, with the vectors and defined as marked in the diagram:
- Getting from point to point we have to go the 'wrong way' down and then the 'right way' along
- It follows that:
- Keeping those things in mind, it is possible to describe any vector that goes from one point to another in the above diagram in terms of a and b
Adding and subtracting vectors follows all the same rules as adding and subtracting letters like x and y in algebra (this includes collecting like terms).It doesn't matter exactly what path you follow through a diagram from starting point to ending point – as long as you add and subtract the general vectors correctly along the path you use, you will get the correct answer.