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

Problem of the week helpp

  1. Dec 14, 2004 #1
    I posted this before, but i messed up on the wording, so heres my repost. My teacher gave us our problem of the week (which was previously on our test), and i have no idea on how to solve it. All i know is that i will probably need to differentiate something, and then find the criticle numbers. OK, so here it goes:

    Use Calculus to prove which vertex angle gives an isosceles triangle the greatest area

    Figure Below
    THank You

    Attached Files:

  2. jcsd
  3. Dec 14, 2004 #2


    User Avatar
    Homework Helper

  4. Dec 14, 2004 #3


    User Avatar
    Science Advisor
    Homework Helper

    I think you were already given the solution someplace else but perhaps you're looking for more detail?

    The first question is do you have any contraints in the problem? For example, is the perimeter of the triangle fixed? I'd guess that the length of the equal sides is fixed since they are labled "K" which suggests a constant.

    In that case the area of the triangle is

    [tex]A = K^2 \sin \frac {\theta}{2} \cos \frac {\theta}{2} = \frac {1}{2}K^2 \sin \theta[/tex]

    where [itex]\theta[/itex] is the vertex angle. Does that help?
  5. Dec 14, 2004 #4

    things seem a bit clearer
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook