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#