Question

( 5 )
4. Given A = î+j+k and B =-1-j-k (A-B)will make
angle with Ā:
(a) 0°
(b) 180°
(c) 90°
(d) 60°​

Answer 1

A - B = 2i + 2j + 2k

so (A-B).A = 6
=> √3.2√3 . cos@ = 6
=> cos@ = 1
=> @ = 0°

OPTION A