Question

Find the angle between the vectors A and B where A= 2i + j - k and B = -i + j- 2k




help please​

Answer 1

Answer:

theta = cos^-1 (1/6)

Explanation:

magnitude of A =

$\sqrt{6}$

magnitude of B =

$\sqrt{6}$

cos theta = A.B/magnitude of A*magnitude of B

= (2i + j - k).(-i + j -2k)/6

= (-2 + 1 + 2)/6

= 1/6

Hence, theeta = cos^-1 (1/6)