# Lesson One

[TOC]

What is vector?

有方向有大小的东西。 So it may not that correct according to vector is a dynamic definition.

Computer Science Perspective:

Vector = Ordered List of Numbers

Ordered reflect the direction

Perspective of Mathematician

Vector Can be anything just guarantee the adding and multiplying of the vectors is meaningful will be fine.

So I get a question about what is the meaning of Vector addition and multiplying?

And they are very important.

Vector Operation

How to think in vector way ? Start from two perspectives:

Arrow

Notice :

One thing you should notice that the arrow should start with origin~

vector coordinate

Number

Understanding from Geometric And Number is pretty important~

Vector 2 Perspective

Let Explain the Vector Basic Conception

1. start from origin
2. Number just tell you the End of the vector cuz every
3. Write vector in Vertical, which called column vector.

column vector

Vector Addition

Head Meet Tail

[Question] Why not All tail start at origin?

Lets come back to the definition of Vector.

If you move the vector that will break the rule that every vector start from origin.

So here we get it, vector is not static definition.

Vector is a movement and what it can do, don't understand it as just a static definition.

Vector is a movement Vecetor is a movement 2

In modern mathematics, there's a tendency to define things in terms of what they do rather than in terms of what they are.

Stack Overflow answer define by usage not what it is

So Lets back to the Addition of the Vectors.

If you want to add two vectors that means you need to move twice. So you should connect them head with tail.

Vector addition

So the multiply of the Vector will not difficult to understand.

Because the multiply is based on the addition.

scaling vector