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!

Gradient vectors

  1. Feb 29, 2012 #1
    1. The problem statement, all variables and given/known data
    My textbook never explains well so I have to figure out how to do problems by reverse engineering using the solution manual. However, here is one operation that I simply cannot reverse engineer. I do not see a common pattern in these four problems. I can't figure out what operation is going on here. In the first one it looks like they're just multiplying i by x and j by y which would work but given the other 3 examples, that's not what's happening. I understand all the other steps but this is one operation that I don't understand.

    Screenshot2012-02-29at72747PM.png

    here are the full problems in case you need to see more context.


    Screenshot2012-02-29at72744PM.png
     
  2. jcsd
  3. Feb 29, 2012 #2

    LCKurtz

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    An appropriate response really depends on what level class you are in. One approach, which works on these problems is to remember if you have an equation ##f(x,y)=c##, which determines y implicitly as a function of x, you have the formula$$
    \frac{dy}{dx}= -\frac{f_x}{f_y}$$For example, in your problem 2 this would give$$
    \frac{dy}{dx}=-\frac x y$$Have you had any differential equations so you can solve this by separation of variables? Like I said, that's not the only way, but I don't know what you have to work with.
     
  4. Feb 29, 2012 #3
    I figure out the operation. You just go back to the original question and plug in the values for x and y into the original equation, simple as that.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Gradient vectors
  1. Gradient of a Vector? (Replies: 11)

  2. Gradient Vector (Replies: 1)

  3. Gradient vector (Replies: 3)

  4. Gradient vector (Replies: 2)

  5. Gradient Vectors (Replies: 21)

Loading...