Question

1. Find the angle between vectors

A = i + 2j-k and B = -4i + j -2k

Answer 1

The angle between two vectors can be found by cos¢ =( ř1 . ř2) /root{(|r1||r2|)}
$\cos(x) = \frac{1 \times - 4 \: + 2 \times 1 \: - 1 \times - 2}{ \sqrt{( {1}^{2} + {2}^{2} + {1}^{2} )( {4}^{2} + {1}^{2} + {2}^{2}) } } \\ or. \cos(x) = \frac{ - 4 + 2 + 2}{ \sqrt{6 \times 21} } = 0 \\ so....x = \frac{\pi}{2}$
So the answer is pi/2
Hope I helped u