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

Need help with using Leibniz's Rule

  1. Dec 17, 2015 #1
    I tried solving this question but I'm not getting the correct answer and I don't know what I'm doing wrong. Can anyone tell me what I did wrong? Thank you.

    The math question is:
    Let g(x) = d/dx (∫x21 et/t dt), then g'(2) is ____?

    The correct answer is e4 but I'm getting 7e4/2. (See my solution attempt in the attached PDF file.)
     

    Attached Files:

  2. jcsd
  3. Dec 17, 2015 #2

    Samy_A

    User Avatar
    Science Advisor
    Homework Helper

    I get the same result as you. Maybe we made the same mistake, or maybe the question was to find ##g(2)##.
     
  4. Dec 17, 2015 #3
    Thank you for your reply.
    The sample question specifically asks for g'(2) but what you say seems to make sense.
    (Although, that would be a he** of a mistake on the part of the school since it's the one of last year's exam questions. :/ )
     
  5. Dec 17, 2015 #4

    Samy_A

    User Avatar
    Science Advisor
    Homework Helper

    Well, everybody can make mistakes. Maybe we did, maybe the school did. Let's wait for others to check the computation.
     
  6. Dec 21, 2015 #5
    If you let g(x) be the integral only. Then the derivative of g(x) at x=2 is e^4. Probably transcription error somewhere.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Need help with using Leibniz's Rule
  1. Leibniz's rule (Replies: 5)

Loading...