T1W7L4: Position Vectors

positon vectors §

• a position vector is a vector used to represent the position of a point (in the cartesian place when working in 2d space) relative to the origin.
• (dont forget that the vector $\vec{O}P$ itself has no fixed position - it just describes the position of P)

why? §

• you can take advantage of it to solve problems in coordinate geometry.
• you cant add coordinates together, but it is something you can do with vectors.
• you can use vector approaches to solve problems within coordinate geometry.

general rule §

$\overrightarrow{AB}=\overrightarrow{OB}-\overrightarrow{OA}$

how is it derived §

• $\overrightarrow{AB}=\overrightarrow{OB}+\overrightarrow{AO}$
• $\overrightarrow{AO=}-\overrightarrow{OA}$ be careful the position vector end point is joint to the start point