Question

A and B are two vectors, what is the angle between (A+B) and (A-B)?

Answer 1

If a is the angle between (A+B) and A, then the angle between (A-B) and A will be 90 -a. Therefore, the angle between (A+B) and(A- B) is a+ 90 -a = 90 degree. The angle between them is 180 Degrees as they are opposite to each other.