Question

What is the dot product of `<2,0,7>` and `<-4,9,-1 >`?

Answer 1

-15

Explanation:

The usual dot product for the vectors `x=(x_1,x_2,...,x_n)` and `y =(y_1,y_2,...,y_n)` in `RR^n` is `x.y = sum_(i=1)^nx_iy_i`.

We apply it here : `(2,0,7).(-4,9,-1) = 2*(-4) + 0*9 + 7*(-1) = -15`