20. Two vectors A and B are such that |A| = 3, |B| = 4, and A.B = -5, find:
(a) the angle between A and B
(b) the length of |A+B| and |A-B|
(c) the angle between (A + B) and (A - B).
20. Two vectors A and B are such that |A| = 3, |B| = 4, and A.B = -5, find:
(a) the angle between A and B
(b) the length of |A+B| and |A-B|
(c) the angle between (A + B) and (A - B).