What is the dot product of <-1,-2,1><1,2,1> and <-1, 2,3 ><1,2,3>?

1 Answer
Mar 17, 2018

The dot product is =0=0

Explanation:

The dot product of 22 vectors < x_1,x_2,x_3><x1,x2,x3> and < y_1,y_2,y_3 ><y1,y2,y3> is

< x_1,x_2,x_3> .< y_1,y_2,y_3 > = x_1y_1+x_2y_2+x_3y_3<x1,x2,x3>.<y1,y2,y3>=x1y1+x2y2+x3y3

Therefore,

< -1, -2, 1> .< -1, 2, 3 > = (-1)*(-1)+ (-2)*(2)+(1)*(3) <1,2,1>.<1,2,3>=(1)(1)+(2)(2)+(1)(3)

=1-4+3=14+3

=0=0

As the dot product is =0=0, the vectors are orthogonal.