What is the dot product of $<7,-3, 9 >$ and $<4,2,-9 >$ ?

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Answer 1 · 2016-07-27T21:04:35

$A*B=-59$

$A= (A_x,A_y,A_z )$

$B=(B_x,B_y,B_z )$

$A.B=(A_x*B_x+A_y*B_y+A_z*B_z)" (Dot product of A and B)"$

$A=<7,-3,9>" ; "B= <4,2,-9>$

$A_x=7" ; "A_y=-3" ; "A_z=9$

$B_x=4" ; "B_y=2" ; "B_z=-9$

$A*B=(7*4+(-3)*2+(-9)*9)$

$A*B=(28-6-81)$

$A*B=28-87$

$A*B=-59$

What is the dot product of <7,-3, 9 ><7,-3, 9 > and <4,2,-9 ><4,2,-9 >?