What is the projection of (3i+2j−6k) onto (3i−j−2k)?

1 Answer
Narad T.
Nov 2, 2016

The answer is =197√14(3i−j−2k)

Explanation:

Let →a=⟨3,−1,−2⟩ and →b=⟨3,2,−6⟩
Then the vector projection of →b upon →a is
→a.→b∥∥∥→a∥∥→b∥∥∥→a
The dot product →a.→b=⟨3,−1,−2⟩.⟨3,2,−6⟩=9−2+12=19
The modulus ∥∥→a∥=√9+1+4=√14
The modulus ∥∥∥→b∥=√9+4+36=√49=7
the projection is =197√14⟨3,−1,−2⟩

Related questions
See all questions in Vector Operations
Impact of this question
1416 views around the world
You can reuse this answer
Creative Commons License