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!

Diff eq directional field

  1. Sep 17, 2006 #1
    Draw a direction field for the given differential equation. Based on the the direction field, determine the behavior of y at t goes to infinity. If this behavior depends on the initial value of y at t=0, describe the dependency.
    y'= -1-2y

    In class we did examples where we had a range. Like we were given y'=2y-3 and told to draw the direction field for -2<y<2 and -2<t<2.
    So for the problem above, how would I find a range, since it wants to infinity?
  2. jcsd
  3. Sep 17, 2006 #2


    User Avatar
    Staff Emeritus
    Science Advisor

    "t going to infinity" doesn'g mean anything here. Your direction field is a graph in an xy-coordinate system and t doesn't have anything to do with it. At every (x, y) point, you want to draw a short vector having slope
    [itex]\frac{dy}{dx}[/itex]. But you are told that the slope is -1- 2y which depends on x only. Should be easy to draw.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Diff eq directional field
  1. Diff. Eq. (Replies: 0)

  2. Diff Eq (Replies: 0)

  3. Diff Eqs (Replies: 2)

  4. Diff eq. (Replies: 4)