Results 1 to 3 of 3

Math Help - A simple question about vectors

  1. #1
    Newbie
    Joined
    Sep 2011
    Posts
    8

    A simple question about vectors

    Hello,
    (see picture)
    could you explain which is correct way to transform first expression into vectors (a or b) and why?


    Thank you
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Oct 2009
    Posts
    5,528
    Thanks
    773

    Re: A simple question about vectors

    If R is the vector from q_1 to q_2 whose length is 1, then the correct expression is (b). This is because a is the angle between R and u, and b is the angle between R (plotted from q_2) and v, so (\vec{R}\cdot\vec{u})=Ru\cos a =u\cos a and (\vec{R}\cdot\vec{v})=Rv\cos b =v\cos b. Dot product uses the angle between the two vectors. If the length of R is not 1, then one has to divide by R^2 (in addition to the division by c^2).
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Banned
    Joined
    Aug 2010
    Posts
    961
    Thanks
    98

    Re: A simple question about vectors

    None of the expressions are vectors???
    Last edited by Hartlw; February 14th 2014 at 09:57 AM.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Help with simple vectors?
    Posted in the Algebra Forum
    Replies: 2
    Last Post: March 19th 2013, 02:39 AM
  2. Simple 3D Vectors question!
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: March 4th 2010, 12:13 PM
  3. simple vectors
    Posted in the Math Topics Forum
    Replies: 2
    Last Post: October 25th 2009, 11:09 AM
  4. Replies: 3
    Last Post: September 20th 2009, 04:11 PM
  5. Simple vectors
    Posted in the Pre-Calculus Forum
    Replies: 7
    Last Post: June 19th 2008, 11:11 AM

Search Tags


/mathhelpforum @mathhelpforum