What is the dot product of $<2,4,7>$ and $<1,-7,7 >$ ?

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Answer 1 · 2018-07-26T05:59:47

The dot product is $=23$

The dot product of $2$ vectors

$veca= < x_1,x_2,x_3>$

and

$vecb= < y_1,y_2,y_3>$

is

$veca.vecb = < x_1,x_2,x_3> . < y_1,y_2,y_3>$

$=x_1y_1+x_2y_2+x_3y_3$

Here the vectors are

$veca = <2,4,7>$ and $vecb = <1,-7,7>$

The dot product is

$<2,4,7> . <1,-7,7> = 2*1+4*(-7)+7*7$

$=2-28+49$

$=23$

What is the dot product of <2,4,7><2,4,7> and <1,-7,7 ><1,-7,7 >?