Co linear points

Announcements Posted on
Four things that unis think matter more than league tables 08-12-2016
    • Thread Starter
    Offline

    0
    ReputationRep:
    Name:  Screen Shot 2016-09-12 at 18.48.15.png
Views: 16
Size:  30.3 KB

    According to the mark scheme the answer is B. I got C but I don't think I full understand the question.

    PQ : PR is equal to 3:5 but it asks for Q : PR and PR is not written as a vector? help
    Offline

    3
    ReputationRep:
    (Original post by Feynboy)

    According to the mark scheme the answer is B. I got C but I don't think I full understand the question.

    PQ : PR is equal to 3:5 but it asks for Q : PR and PR is not written as a vector? help
    You can find the vector PR because you can find R since you're given the vector from Q to R, and the point Q itself.
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by RDKGames)
    You can find the vector PR because you can find R since you're given the vector from Q to R, and the point Q itself.
    Find R by saying QR = R - Q

    Find PR by saying PR = R - P as we now know R and were given P.


    But they don't equate to 3:2 for Q : PR is what I'm doing right
    Offline

    3
    ReputationRep:
    (Original post by Feynboy)
    Find R by saying QR = R - Q

    Find PR by saying PR = R - P as we now know R and were given P.


    But they don't equate to 3:2 for Q : PR is what I'm doing right
    Okay I think you're thinking it about it the wrong way.

    Find PR and get its magnitude.

    Find PQ and get its magnitude.

    You should find that, with magnitude concerned, PQ + QR = PR and you can find QR since you know the other two. Things should cancel and you'd be left with 3+2=5; therefore Q, being between P and R, would split the overall length PR into 3:2
 
 
 
Write a reply… Reply
Submit reply

Register

Thanks for posting! You just need to create an account in order to submit the post
  1. this can't be left blank
    that username has been taken, please choose another Forgotten your password?
  2. this can't be left blank
    this email is already registered. Forgotten your password?
  3. this can't be left blank

    6 characters or longer with both numbers and letters is safer

  4. this can't be left empty
    your full birthday is required
  1. Oops, you need to agree to our Ts&Cs to register
  2. Slide to join now Processing…

Updated: September 12, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

Poll
Do you think you'll achieve your predicted A Level grades?
Useful resources

Make your revision easier

Maths

Maths Forum posting guidelines

Not sure where to post? Read here first

Equations

How to use LaTex

Writing equations the easy way

Student revising

Study habits of A* students

Top tips from students who have already aced their exams

Study Planner

Create your own Study Planner

Never miss a deadline again

Polling station sign

Thinking about a maths degree?

Chat with other maths applicants

Can you help? Study help unanswered threads

Groups associated with this forum:

View associated groups
Study resources

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Quick reply
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.