What is the dot product of <5,1,7> and <8,4,9>?

2 Answers

The dot product of two three dimensional vectors is defined as

ab=axbx+ayby+azbz

In our case a=(5,1,7) and b=(8,4,9)

hence

ab=58+1479=19

Jan 3, 2016

19

Explanation:

To do the dot product, you multiply together the corresponding components, and then sum the results. In general:
(a1,a2,a3)(b1,b2,b3)=(a1b1+a2b2+a3b3)

So in your case:

(58)+(14)+(79)
=40+463
=19