Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Find math maximum homework

  1. May 26, 2004 #1
    I've got an assesment task tommorow and one of the questions on the practice exam has got me stumped
    The eqaution is y=21xe^(-.9x) - 12xe^(-.6x)

    The question asks to show how the maximum can be
    e^(0.3x) = 70-63x/40-24x

    If differentiated it and taken out the common factors to get
    21e^(-.9x)(-.9x + 1) - 12e^(-.6x)(-.6x + 1) = 0

    but have no idea how to make it e^(0.3x) = 70-63x/40-24x

    If any one could help i would really appreciate it
  2. jcsd
  3. May 26, 2004 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    First of all, write the answer properly:
    Rewrite the right-hand side as:

    See if you can relate this last expression to the equation giving the critical value for y.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Find math maximum homework