Question

If `A= <-2 ,3 ,3 >` and `B= <-9 ,4 ,8 >`, what is `A*B -||A|| ||B||`?

Answer 1

5.514

Explanation:

Dot product A.B=(-2)(-9)+(3)(4)+(3)(8) = 54

`||A||= sqrt((-2)^2+3^2 +3^2)=sqrt22`

`||B||= sqrt((-9)^2+ 4^2+8^2)=sqrt161`

Therefore `A.B-||A|| ||B||= 54-sqrt22 sqrt161`= -5.514