Question

Find the dot product of the position vectors whose terminal points are (8, 6) and (15, 8).

A.37
B. 72
C. 154
D.168

Answer 1

dot product = 6*8 + 8*15
= 48 + 120
= 168

Answer 2

Option D

Explanation:

Given are two position vectors in two dimension.

They are (8,6) and (15,8)

We have to find the dot product.

We know that if

`a=a1i+a2j+a3k \\b = b1i+b2j+b3k\\a.b = a1b1+a2b2+a3b3`

Here two dimension

Hence dot product =
`8(15)+6(8)\\= 8(21)\\= 168`

Option D is right