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!

Need Help with a Derivative

  1. Sep 25, 2009 #1
    Need Help with a Derivative!!

    1. The problem statement, all variables and given/known data
    {6x+[8x^(1/2)]}^(1/2)


    2. Relevant equations

    I know its chain rule with a square root inside a square root but i can not seem to get the right answer to enter into the computer program my college uses

    3. The attempt at a solution
     
  2. jcsd
  3. Sep 25, 2009 #2
    Re: Need Help with a Derivative!!

    So you want help to rewrite it in a way that will work in the program?
    Try entering it with just parentheses ().
     
  4. Sep 25, 2009 #3
    Re: Need Help with a Derivative!!

    No i can not seem to get the solution
     
  5. Sep 25, 2009 #4
    Re: Need Help with a Derivative!!

    The square root inside a square root is throwing me off
     
  6. Sep 25, 2009 #5
    Re: Need Help with a Derivative!!

    Is this what it looks like?

    [tex]\sqrt{6x + 8\sqrt{x}}[/tex]
     
  7. Sep 25, 2009 #6
    Re: Need Help with a Derivative!!

    no the 8 is also inside the inner square root
     
  8. Sep 25, 2009 #7
    Re: Need Help with a Derivative!!

    You didn't use parentheses correctly, then. 8x needs to be in parentheses.

    {6x+[(8x)^(1/2)]}^(1/2)
     
  9. Sep 25, 2009 #8
    Re: Need Help with a Derivative!!

    Ok but that is the problem and i need the solution
     
  10. Sep 25, 2009 #9
    Re: Need Help with a Derivative!!

    How are you entering it into the program?
     
  11. Sep 25, 2009 #10
    Re: Need Help with a Derivative!!

    (1/2){[6+(8x)^(1/2)]^(-1/2)}{6+(4x)^(-1/2)]
     
  12. Sep 25, 2009 #11
    Re: Need Help with a Derivative!!

    Have you tried with just parentheses () and no square brackets [] or curly braces {} ?
     
  13. Sep 25, 2009 #12
    Re: Need Help with a Derivative!!

    yes but this provides me with the answer i have worked out which is (1/2){6+(8x)^(1/2)]^(-1/2)}[6+(1/2)(8x)^(-1/2)](1/2)[(8x)^(-1/2)](8) and the hint says "You start
    with (6x+(8x)^.5))^.5. The inside is (6x+(8x)^.5). So, use the chain
    rule on that. Once you have that and have to take the derivative of the
    inside, then you need to also do the chain rule with the inside of 8x."
     
  14. Sep 25, 2009 #13
    Re: Need Help with a Derivative!!

    So you're having trouble doing it by hand on paper?
     
  15. Sep 25, 2009 #14
    Re: Need Help with a Derivative!!

    i guess..if my answer doesnt look right, but i believe i am getting the right answer
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Need Help with a Derivative
  1. Need help derivation (Replies: 6)

Loading...