If $A = < - 2, 4, 3 >$ $A= <-2 ,4 ,3 >$ and $B = < - 1, 2, 8 >$ $B= <-1 ,2 ,8 >$ , what is $A \cdot B - | | A | | | | B | |$ $A*B -||A|| ||B||$ ?

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Answer 1 · 2016-10-14T20:14:17

$34 - \sqrt{29 \cdot 69}$ $34-sqrt(29*69)$

$A . B = 2 + 8 + 24 = 34$ $A.B=2+8+24=34$

$∥ ∥ A ∥ = \sqrt{4 + 16 + 9} = \sqrt{29}$ $∥A∥ =sqrt(4+16+9)=sqrt29$

$∥ ∥ B ∥ = \sqrt{1 + 4 + 64} = \sqrt{69}$ $∥B∥=sqrt(1+4+64)=sqrt69$

$A . B - ∥ A ∥ ∥ B ∥ = 34 - \sqrt{29 \cdot 69}$ $A.B- ∥A∥∥B∥=34-sqrt(29*69)$

If A=<−2,4,3>A= <-2 ,4 ,3 > and B=<−1,2,8>B= <-1 ,2 ,8 >, what is A⋅B−||A||||B||A*B -||A|| ||B||?