Question

1. Find the vector passing through the point A( 1, 2, -3) and B(-1, -2, 1).

2. Find the direction cosines along AB.

Answer 1

1. \(\overline{AB}\)= \(\overline{OB}\) – \(\overline{OA}\) = -i – 2j + k – (i + 2j – 3k) = -2i – 4j + 4k.

2. Unit Vector

Direction cosines are \(\frac{-2}{6}, \frac{-4}{6}, \frac{4}{6}\)