AB up y axis from (0,0) s to (0,s)
then BC right s (s,s)
then CD down s to (s,0)
then DA left to (0,0)
O at (x,y)
a = -x i - y j
b = -x i + (s-y) j
c = (s-x)i (s-y) j
unknown d = (s-x)i - y j
c + a - b = (s-x)i +(s-y)j-y j -(s-y)j
= (s-x)i - y j (Caramba)
so I get
d = c + a - b
I understand that the answer to this is a+b-c, but I'm not sure how to show working out for this. Any help would be great.
" O is any point in the plane of the square ABCD. The vectors OA, OB and OC are a, b and c respectively. Find the vector OD, in terms of a, b and c.
Thanks!
1 answer
2 answers