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: Derivative of a Vector Function

  1. Jul 13, 2014 #1
    1. The problem statement, all variables and given/known data

    r(t) = ln ti + j, t > 0

    find r′ (t) and r″(t)

    2. Relevant equations


    3. The attempt at a solution

    r'(t)= 1/t i

    am I on the right track? The answer in the back is r'(t)= 1/t i -1/t^2 j

    Please help asap this is quite urgent! Thank you!
    Last edited: Jul 13, 2014
  2. jcsd
  3. Jul 13, 2014 #2

    Char. Limit

    User Avatar
    Gold Member

    That doesn't make too much sence if r(t) is supposed to be constant along the j unit vector. My best guess is that it's probably a misprint, and that r(t) is supposed to be r(t)=ln(t) i + 1/t j. That said, if this is for an assignment, proceed with the problem as written, which you're on the right track so far.
  4. Jul 13, 2014 #3
    yea that's what I originally thought too, thanks a bunch! (:
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted