The component form of a vector of initial point A and terminal point B is given by:

Substitute B=(0,3) and A=(1,2):

Substract the corresponding coordinates of the points:

Therefore, the component formt of the vector AB is:

Which can also be written in terms of the unit vectors:

Or in terms of the X and Y components:

The magnitude of a vector its given by:
![|\vec{AB}|=\sqrt[]{(AB_x)^2+(AB_y)^2}](https://img.qammunity.org/2023/formulas/mathematics/college/j2lww0rs6an8hhjh5970st8ijstdhg852j.png)
Substitute the corresponding values of its components:
![|\vec{AB}|=\sqrt[]{(-1)^2+(1)^2}=\sqrt[]{1+1}=\sqrt[]{2}\approx1.414](https://img.qammunity.org/2023/formulas/mathematics/college/uwx6g13ukx313c3xeyqtamayqh016np0ux.png)