What is the dot product of $<9,4,1>$ and $<-5,1,7 >$ ?

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Answer 1 · 2016-02-05T19:47:53

$A.B=-34$

$A=( A_i , A_j ,A_k)$
$B=(B_i ,B_j ,B_k)$
$A.B=(A_i.B_i + A_j.B_j +A_k.B_k)$
$A.B=(-5.9 +4.1 +1.7)$
$A.B=-45 + 4 +7$
$A.B=-34$

What is the dot product of <9,4,1><9,4,1> and <-5,1,7 ><-5,1,7 >?