1. Not finding help here? Sign up for a free 30min 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!

Another vector

  1. Sep 16, 2007 #1
    Given d1 + 8d2 = 5d3, d1 - d2 = 9d3, and d3 = 2 i + 4 j, what are the following vectors?

    (a) d1 =
    (b) d2 =

    I keep trying to do substituting equations, but I am getting them wrong, and help?
     
  2. jcsd
  3. Sep 16, 2007 #2

    Dick

    User Avatar
    Science Advisor
    Homework Helper

    You'll need to show an example of how you are getting them wrong before anyone can help. It's actually a pretty easy problem.
     
  4. Sep 16, 2007 #3
    easy, fooled me then
    D3=2i+4j
    d1=5d3-8d2
    d2=-9d3+d1

    so i am trying to combine these to give me the value of either only d1 or only d2, and no matter how I mess with them, I can't seem to be able to do it.

    d1=10i+20j-18j-36j-d1 so I cant do this, plus its wrong

    idk did I mess up the subbing eq's?
     
  5. Sep 16, 2007 #4

    Dick

    User Avatar
    Science Advisor
    Homework Helper

    Try subtracting the first two equations from each other. Doesn't that get rid of d1?
     
  6. Sep 16, 2007 #5
    could you be a a little more specific and in dx-dy and do you mean set equal or subtract?
     
  7. Sep 16, 2007 #6
    You could do either a substitution or a subtraction. You will either see that d1 = blah, or eqn1 - eqn2 = something*d2 = blap - bleh.
     
    Last edited: Sep 16, 2007
  8. Sep 16, 2007 #7

    Dick

    User Avatar
    Science Advisor
    Homework Helper

    I mean (d1+8d2)-(d1-d2)=5d3-9d3. What's that?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Another vector
  1. Another vector ? (Replies: 2)

  2. Another vector problem (Replies: 1)

Loading...