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: Arc length multivariate calc

  1. Oct 24, 2004 #1
    here is the problem, and I cant seem to get very far,

    compute the length of r(t) = <3t, 4cost, 4sint> from t=0 to t=1

    i know the formula is integral from 0 to 1 of length of r'(t)

    but I keep coming up with 5, and it doesnt seem right, can someone please confirm or deny this. Thanks
     
  2. jcsd
  3. Oct 24, 2004 #2
    that seems to be what i get too. r'(t) = 5, so when you integrate this from 0 to 1 it gives you 5 again.
     
  4. Oct 24, 2004 #3

    robphy

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    If you look at what you've plotted, i believe it is the hypotenuse of a right triangle with base 4 and height 3 wrapped around a cylinder [of radius 4].
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook