lhh2003
Badges: 18
Rep:
?
#1
Report Thread starter 1 year ago
#1
Hi guys, in this question, I don't get why they have subtracted Vector B from Vector A ?

Given that the point A has position vector –5i + 7j and the point B has position vector –8i + 2j
(a) Find the vector AB.
0
reply
RDKGames
Badges: 20
Rep:
?
#2
Report 1 year ago
#2
(Original post by lhh2003)
Hi guys, in this question, I don't get why they have subtracted Vector B from Vector A ?

Given that the point A has position vector –5i + 7j and the point B has position vector –8i + 2j
(a) Find the vector AB.
The other way round; vector A from vector B. And it's because of the following argument.



Suppose you start at the origin (from which every point is measured from) and you want to get to point B. Obviously, you can just travel along the vector OB which is -8i + 2j.

But you can also get to B via detour through A. So you can go to A first, then from A go to B. This is given in terms of vectors as OA + AB.

The result is the exact same displacement vector because both ways make you end up at B. Hence, OB = OA + AB.

And I'm sure you can see why AB = OB - OA now.
Last edited by RDKGames; 1 year ago
0
reply
lhh2003
Badges: 18
Rep:
?
#3
Report Thread starter 1 year ago
#3
(Original post by RDKGames)
The other way round; vector A from vector B. And it's because of the following argument.



Suppose you start at the origin (from which every point is measured from) and you want to get to point B. Obviously, you can just travel along the vector OB which is -8i + 2j.

But you can also get to B via detour through A. So you can go to A first, then from A go to B. This is given in terms of vectors as OA + AB.

The result is the exact same displacement vector because both ways make you end up at B. Hence, OB = OA + AB.

And I'm sure you can see why AB = OB - OA now.
I don’t get why it wouldn’t be Ab average if the two.

Say Vector A = 4i + 5j , and Vector B = 5i + 7j.

Surely the resultant vector would be 5.5i + 6j ? It doesn’t make sense why the resultant vector would go out of the range of Ai to Bi for example.
0
reply
RDKGames
Badges: 20
Rep:
?
#4
Report 1 year ago
#4
(Original post by lhh2003)
I don’t get why it wouldn’t be Ab average if the two.

Say Vector A = 4i + 5j , and Vector B = 5i + 7j.

Surely the resultant vector would be 5.5i + 6j ? It doesn’t make sense why the resultant vector would go out of the range of Ai to Bi for example.
The resultant vector is what you get when you add up all of the vector. Not when take the average. I'm not sure where you're getting this idea from. You need to stick with the definitions for these things.
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

Do you think receiving Teacher Assessed Grades will impact your future?

I'm worried it will negatively impact me getting into university/college (43)
37.07%
I'm worried that I’m not academically prepared for the next stage in my educational journey (11)
9.48%
I'm worried it will impact my future career (5)
4.31%
I'm worried that my grades will be seen as ‘lesser’ because I didn’t take exams (29)
25%
I don’t think that receiving these grades will impact my future (18)
15.52%
I think that receiving these grades will affect me in another way (let us know in the discussion!) (10)
8.62%

Watched Threads

View All