Question

If `A= <-5 ,6 ,-3 >` and `B= <-6 ,-4 ,4 >`, what is `A*B -||A|| ||B||`?

Answer 1

`~~-75`

Explanation:

`A*B = (-5*-6) + (6*-4)+ (-3*4) = -6`
`||A|| = sqrt((-5)^2 + (6)^2+ (-3)^2) = sqrt(70)`
`||B|| = sqrt((-6)^2 + (-4)^2+ (4)^2) = sqrt68`

putting it together

`A*B-||A||||B|| =-6 - sqrt(70*68) ~~-75`