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: :Implicit Differentiation Problem - Check my work?:

  1. Oct 2, 2005 #1
    :Implicit Differentiation Problem -- Check my work?:

    Think I placed this in the wrong forum...

    I've worked it -- can someone just check my work?

    Problem:

    xcosy+ycos=1

    My work:

    [x (d/x)cosy + cosy (d/dx)x] + [y (d/dx)cosx + cosx (d/dx)y] = (d/dx) 1

    -xsiny (dy/dx) + cos y - ysinx + cos x (dy/dx) = 0

    -xsiny (dy/dx) + cos y = ysinx - cosy

    dy/dx = (ysinx - cosy)/(-xsiny + cos x)


    Meanwhile, could someone help me with this one...

    squareroot (xy) = 1+(x^2)y
     
  2. jcsd
  3. Oct 2, 2005 #2
    this final answer is right.

    The second one is probably easier, have a go at it at least and we'll check the answer again?
     
  4. Oct 2, 2005 #3
    Well, the problem with that one is the idea that I can't even get the first step... the derivative of sqrt (xy)
     
  5. Oct 2, 2005 #4
    Square the equation.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook