Question

39. A and B are two points with position vectors
a,b respectively. If the points C and D have
3a +5b/8
position vectors 5a-4b and
then
8
prove that A, B, C and D are collinear. ​

Answer 1

Answer:

What do you know about the directions of vectors A and B If the dot product is positive?

If the dot product is positive then the angle q is less then 90 degrees and the each vector has a component in the direction of the other. If the dot product is negative then the angle is greater than 90 degrees and one vector has a component in the opposite direction of the other.

Explanation: