1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Coordinates of a point in 3D provided connecting points are known

  1. Oct 22, 2009 #1
    Hi ,


    Given 3 points A[x1,y1,z1], B[x2,y2,z2] and C, and given the distance between B and C is known and the angle ABC is supplied. How do we ascertain the coordinates of the point C ?

    I can calculate the dot product using the angle, by defining vectors BC and AC and then use the distance formula to get another equation for the coordinates of C. But I have a hunch that there is a simpler way to do this. I need to program this, and therefore the requirement for a simpler solution.

    If there is a derivation that you know please point me towards it.

    Thanks a lot in advance.


    MORE Information Added:

    I didn't include all the information earlier and yes Mathman is right that as stated this problem doesn't have a unique solution. This is actually a smaller part of the bigger problem I have. Here it goes.

    A-B-C-D are 4 points. We define rx = length(B-C), angle, eta = (A-B-C) and angle theta = (B-C-D) and the torsion angle omega= (A-B-C-D). What I really need to do is to find the coordinates of C and D provided that I have the new values of rx, eta, theta and omega. Any pointers would be welcome.

    Thanks again.
     
    Last edited: Oct 22, 2009
  2. jcsd
  3. Oct 22, 2009 #2

    mathman

    User Avatar
    Science Advisor
    Gold Member

    The problem as stated does not have enough information to get a unique solution for C. Since the problem is 3d, there will be a circle of points satisfying the requirements.
     
  4. Oct 22, 2009 #3
    I have added more information; please take a look if you get a chance ! Thank a lot.
     
  5. Oct 22, 2009 #4
    You want to find 2 unknown points knowing 1 length and 3 angles. That can't be done either.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Coordinates of a point in 3D provided connecting points are known
Loading...