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!

Homework Help: Equations of Lines/Multivariable Calculus

  1. Sep 14, 2013 #1
    1. The problem statement, all variables and given/known data

    Determine whether the lines
    L1:x=t, y=16+4t ,z=8+t
    L2:x=−7+2t, y=−8+6t, z=−3+4t
    intersect, are skew, or are parallel. If they intersect, determine the point of intersection

    2. Relevant equations

    t = -7 + 2s

    16 + 4t = -8 + 6s

    8 + t = -3 + 4s

    3. The attempt at a solution

    I solved the first two equations for s and t then plugged them into the third which confirmed that the lines intersect. To determine the point of intersection, I figured that setting the parametric equations equal to each other and solving for t would give the correct answer, but that doesn't seem to be the right way (I got 7 for the x-coordinate of the intersection).

    So my question is how do I find the intersection?
  2. jcsd
  3. Sep 14, 2013 #2
    Once you found out that the lines interesected by solving for t and s, substituting either t in L1 or s in L2 would give you the point of intersection. They should match up if you do both. (And I'm not sure about 7 for the x-coordinate, double check your math).
  4. Sep 14, 2013 #3
    Yep, you're right, thanks! It worked.
  5. Sep 14, 2013 #4
    Sure thing!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted