VECTORS

 

i,j notation

Vectors can be described by their horizontal (i) and vertical (j) displacements

  

 

Adding and Subtracting

Deal with i and j parts independently

 

(3i + 5j) + (2i  4j)

= (3 + 2)i + (5  4)j

= 5i + j

 

Multiples

Expand brackets as normal, then combine I and j parts.

 

5(3i + 7j) + 3(2i  4j)

= 15i + 35j +6i  12j

= (15 + 6)i + (35  12)j

= 40i + 23j