The position vectors of the points A, B, C of a parallelogram ABCD are a, b, and c respectively. How do I express, in terms of a, b and, the position vector of D?
Suppose that, the position vector (pv) of the point
We dnote this by
Now, we know from Geometry that, the diagonals
of a parallelogram
Therefore, the mid-point of the diagonal
But, the pv. of