Question

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

Answer 1

`a*b=-7`

Explanation:

`a=a__i +a_j+a_k`
`b=b_i+b_j+b_k`
`a*b=a_i*b_i+a_j*b_j+a_k*b_k`
`a*b=(-1*-2)+(1*-8)+(2*-1)`
`a*b=2-8-1`
`a*b=-7`