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). Scalars and Vectors problem no 20. Sindh Textbook Board (stb) problems

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).