1. Limited time only! Sign up for a free 30min personal 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!

Maximum/Minimum-Check Please?

  1. Jun 13, 2013 #1
    1. The problem statement, all variables and given/known data
    Find the maximum and minimum values on the function: y= (x^2)(e^(-x)) on the interval [-10, 10].

    2. Relevant equations

    3. The attempt at a solution
    f'(x)= 2x*(e^(-x)) - (e^(-x)*(x^2))
    f'(x)= x*e^(-x) (2- x)
    Solve for zero, for critical points? I got two solutions: x=0 or x= 2

    Plugging these two critical points and the endpoints on the interval back into f(x), I get:
    (0, 0) - Minimum
    (2, 4/(e^2) )
    (-10, 100*(e^10) ) - Maximum
    (10, 100/(e^10) )

    Is this right? Thank you.
  2. jcsd
  3. Jun 13, 2013 #2


    Staff: Mentor

    You don't "solve for zero", but I know what you mean - Set f' = 0 and solve that equation.
    Your max and min look OK, but check this point (10, 100/(e^10) ).
  4. Jun 13, 2013 #3
    Okay, I'll make sure. Thank you!
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted

Similar Threads - Maximum Minimum Check Date
Minimum/Maximum problem Mar 15, 2018
Maximum/minimum problem Mar 11, 2018
Maximum-minimum area from a fixed length rope Nov 17, 2017
Local minimum and maximum Nov 14, 2017
Minimum-maximum problem with graph plotting Nov 3, 2017