What is the dot product of $< - 8, 1, 2 >$ $<-8,1,2 >$ and $< - 2, 5, - 1 >$ $<-2,5,-1 >$ ?

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Answer 1 · 2018-05-18T05:39:33

The answer is $= 19$ $=19$

The dot product of $2$ $2$ vectors

$\to x = < a, b, c >$ $vecx= < a,b,c >$

and

$\to y = < d, e, f >$ $vecy = < d,e,f >$

is

$\to x . \to y = < a, b, c > . < d, e, f > = a d + b e + c f$ $vecx . vecy = < a,b, c> . < d, e, f > =ad+be+cf$

Therefore,

$< - 8, 1, 2 > . < - 2, 5, - 1 > = (- 8) \cdot (- 2) + (1) \cdot (5) + (2) \cdot (- 1)$ $< -8,1,2 > . < -2, 5, -1> = (-8)*(-2)+(1)*(5)+(2)*(-1)$

$= 16 + 5 - 2$ $=16+5-2$

$= 19$ $=19$

What is the dot product of <−8,1,2><-8,1,2 > and <−2,5,−1><-2,5,-1 > ?