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: Length of spiral

  1. Sep 26, 2004 #1
    a spiral given by r(t) = (e^-t cos t, e^-t sin t) , t is greater than or equal to 0, how would i find the length of the spiral?
    thanks anyone!
  2. jcsd
  3. Sep 26, 2004 #2
    do a line integral. length = S(dr) from t = 0 on out to infinity in this case. dr is sqrt(dx^2+dy^2) (assuming this is two and not three dimensions) where dx is the derivative of the i component of r(t) and dy is the derivative of the j component of r(t). Oh sorry S also means integral in my bastardized way of writing math with basic text.
    Last edited by a moderator: Sep 26, 2004
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook