Results 1 to 6 of 6

Math Help - collinear vectors

  1. #1
    Newbie
    Joined
    Apr 2008
    Posts
    16

    collinear vectors

    Describe a how you use vectors to determine if three given points are collinear ?
    Test your method using the set of points p(-3,1) q(2,4) r(5,6)
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Moo
    Moo is offline
    A Cute Angle Moo's Avatar
    Joined
    Mar 2008
    From
    P(I'm here)=1/3, P(I'm there)=t+1/3
    Posts
    5,618
    Thanks
    6
    Hello,

    Two vectors \vec{a} and \vec{b} are colinear if there exists a real number \lambda different from 0 such as \vec{a}=\lambda \vec{b}

    If three points are colinear, then two vectors joining two of them are colinear.. This means that if there are A, B and C three different points, and that you want to show that they are colinear, you just have to prove that \vec{AB} and \vec{AC}, for example, are colinear.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,801
    Thanks
    1691
    Awards
    1
    Quote Originally Posted by fastman390 View Post
    Describe a how you use vectors to determine if three given points are collinear ?
    Test your method using the set of points p(-3,1) q(2,4) r(5,6)
    You can see that \overrightarrow {pq}  = \left\langle {5,3} \right\rangle \,\& \,\overrightarrow {pr}  = \left\langle {8,5} \right\rangle
    Are those vectors multiples of each other (i.e. parallel)?
    If yes then you can say that they are collinear in \Re^2.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Moo
    Moo is offline
    A Cute Angle Moo's Avatar
    Joined
    Mar 2008
    From
    P(I'm here)=1/3, P(I'm there)=t+1/3
    Posts
    5,618
    Thanks
    6
    Hello Plato,

    I just have a question :

    Is it \Re or \mathbb{R} you use in the USA (or anywhere you are )?
    Follow Math Help Forum on Facebook and Google+

  5. #5
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,801
    Thanks
    1691
    Awards
    1
    Quote Originally Posted by Moo View Post
    Is it \Re or \mathbb{R} you use in the USA?
    Both are in use. About 10 years or more ago there was in fact a bitter argument afoot about the use of the so-called ‘blackboard font’. There were some very prominent names in the editorial circles who were against. I have forgotten the details. For me I don’t really care. When I am just quickly typing it is easier to use \Re rather than \mathbb{R}. I tend use the latter if I am also using MathType.
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Moo
    Moo is offline
    A Cute Angle Moo's Avatar
    Joined
    Mar 2008
    From
    P(I'm here)=1/3, P(I'm there)=t+1/3
    Posts
    5,618
    Thanks
    6
    Ok, thanks for the information
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 1
    Last Post: June 6th 2010, 09:29 AM
  2. Replies: 1
    Last Post: October 25th 2009, 12:15 PM
  3. Prove that P, Q, M, N are collinear
    Posted in the Geometry Forum
    Replies: 0
    Last Post: October 20th 2008, 04:43 AM
  4. Collinear Points
    Posted in the Geometry Forum
    Replies: 1
    Last Post: April 19th 2008, 05:04 PM
  5. Collinear points
    Posted in the Geometry Forum
    Replies: 2
    Last Post: December 26th 2006, 09:46 PM

Search Tags


/mathhelpforum @mathhelpforum