Define Vector on x-Axis: -d/2 to d/2

[Philosophaie]

How do I define a vector starting on the x-Axis at -d/2 ending at d/2 on the x-Axis?

 

[fresh_42]

How do I define a vector starting on the x-Axis at -d/2 ending at d/2 on the x-Axis?

You define it as $(d)$.

A vector notation doesn't say anything about where it is applied at. It simply has a length - here $d$ - and a direction - here only in one coordinate, so $(*)\,$. If you want to describe a vector as its point of application and its length and direction, then you need to use pairs $(p;\vec{v})$. Here it would be $(p;\vec{v})=(-\frac{d}{2};d)$.