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!

Optimization finding expression

  1. Mar 26, 2006 #1

    I drew out that diagram but I think I might be wrong. The question is:

    Tom makes an open box from a rectangular piece of metal by cutting equal squares from the four corners and turning up the sides. The piece of metal measures 60 x 100 cm. What are the dimensions of the box with the maximum volume?
  2. jcsd
  3. Mar 26, 2006 #2
    I wrote A=(60-2x)(100-2y)
  4. Mar 26, 2006 #3
    [tex]V = l.w.h[/tex]
    [tex]V = (100-2y)(60-2x)(y)[/tex]

    If he cut squares from the four corners, then y = x.

    [tex]V = (100-2x)(60-2x)(x)[/tex]

    Find the maximum value of V for positive values of x and you have your solution.
  5. Mar 26, 2006 #4
    OHH...Right. Okay, thank you!
  6. Mar 26, 2006 #5
    Okay this is strange...
    After expanding and simplifying, I get

    I differentiate that too

    but I'm not getting the answer in the textbook. What am I doing wrong?
  7. Mar 26, 2006 #6
    nvm...I should have differentiated using the product rule D8
  8. Mar 26, 2006 #7
    no...didn't make a different and Im still getting a weird answer. Can someone please help me?
  9. Mar 26, 2006 #8
    Ignore last post! D8
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Optimization finding expression
  1. Finding Expressions (Replies: 7)

  2. Finding an expression (Replies: 4)