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!

Dot product

  1. Mar 15, 2013 #1
    Find 2 unit vectors that make a 60 degree angle with <3,4>

    Vector <a,b>
    Taking b=1 cos60=1/2

    3a+4=(5/2 )sqrt(a^2+1)

    36a^2+96a+64=25a^2+25
    11a^2+96a=-39
    (sqrt(11)a+48)^2= 2265
    +- a=(sqrt(2265)-48)/sqrt(11)
     
  2. jcsd
  3. Mar 15, 2013 #2

    Curious3141

    User Avatar
    Homework Helper

    I don't see a question here.

    But let me preempt it with a question of my own. You're asked to find unit vectors. Can you think of another condition you can impose on a and b to meet this requirement?

    It's fine to do it the way you did (letting b = 1), but then you still have to find unit vectors in those directions. More work.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Dot product
  1. Dot product (Replies: 2)

  2. Dot product (Replies: 2)

  3. Dot product (Replies: 5)

  4. Dot product (Replies: 1)

Loading...