Recent content by Oglethorpe

  1. O

    Maximize f(x,y,z) with Lagrange Multipliers

    Find the maximum value of f(x,y,z) = 5xyz subject to the constraint of [PLAIN]http://www3.wolframalpha.com/Calculate/MSP/MSP9619f6019f3fia87i60000567g3gb3dhi833if?MSPStoreType=image/gif&s=6&w=126&h=20. I know to find the partial derivatives of the function and the constraint. Then, set up...
  2. O

    Local Extrema with Partial d/dx

    Oh! I typed f_x=2x-y when I should've typed f_x=2x-y-9
  3. O

    Local Extrema with Partial d/dx

    Why would that be? And yes, I get f_xx=2 f_xy=-1 f_yy=2
  4. O

    Local Extrema with Partial d/dx

    Oh thanks, and I simplified the f_x to y=2x-9, which I then substituted into f_y and went from f(y)=-x+2y+6 to -2x+9+4x-18+6=0, which simplifies to 2x-3=0 resulting in x=3/2. I'm more curious on how to take a second derivatives test when there are no variables to plug in a critical point, however.
  5. O

    Local Extrema with Partial d/dx

    Hello, I'm been stuck on this problem and I've been staring blankly at it way too long. I stumbled upon here and thought I'd ask for help? :P Alright well, I'm looking for a local max/min, and I've already done the first partials and I got *f(x)=2x-y and f(y)=-x+2y+6; I'm sure those are right...