Question

If `A = <4 ,3 ,-7 >`, `B = <5 ,8 ,-3 >` and `C=A-B`, what is the angle between A and C?

Answer 1

80.71 deg

Explanation:

C = ( `-`1, `-`5, `-`4 )
The angle between vectors ( x, y, z ) and ( u, v, w )
= arc cos { (xu + yv + zw ) / (`sqrt` ( x^2 + y^2 + z^2 )`sqrt`( u^2 + v^2 + w^2))}
Here, the angle is arc cos ( 9 / `sqrt`3108)