What is the dot product of $< 5, 6, - 3 >$ $<5,6,-3 >$ and $< - 4, 8, - 5 >$ $<-4,8,-5 >$ ?

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Answer 1 · 2015-12-26T13:49:36

$43$ $43$

The classic euclidian scalar product is given by the following formula : $AA x=(x_1,...,x_n),y=(y_1,...,y_n) in RR^n : x.y = sum_(i=1)^n x_iy_i$ .

We apply it here : $(5,6,-3).(-4,8,-5) = 5*(-4) + 6*8 + (-5)*(-3) = -20 + 48 + 15 = 43$

What is the dot product of <5,6,-3 ><5,6,−3><5,6,-3 > and <-4,8,-5 ><−4,8,−5><-4,8,-5 >?