Question

If `A= <-2 ,1 ,3 >` and `B= <-9 ,2 ,8 >`, what is `A*B -||A|| ||B||`?

Answer 1

`44-sqrt2086`

Explanation:

`A*B = (-2)*(-9)+(1)*(2)+(3)*(8)`
`= 44`

`||A|| = sqrt{(-2)^2+(1)^2+(3)^2}`
`= sqrt14`

`||B|| = sqrt{(-9)^2+(2)^2+(8)^2}`
`= sqrt149`

`A*B-||A||*||B|| = 44-sqrt2086`