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: Slope of the tangent line of an intersection - Directional Derivatives

  1. May 9, 2010 #1
    1. The problem statement, all variables and given/known data
    Find the slope of the tangent line to the curve of intersection of the vertical plane x - y + 1 =0 and the surface z = x2+y2 at the point (1, 2, 5)


    2. Relevant equations
    Gradients, Cross products


    3. The attempt at a solution

    I'm pretty lost here. I think I have to cross the two gradients of the functions that I have to find the intersection at (1, 2, 5). However, what then?
     
  2. jcsd
  3. May 10, 2010 #2

    lanedance

    User Avatar
    Homework Helper

    how about finding the horizontal direction of the plane, then using it to find the directional derivative....
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook