Results 1 to 5 of 5
Like Tree1Thanks
  • 1 Post By ibdutt

Math Help - First and second derivatives

  1. #1
    Member
    Joined
    Sep 2012
    From
    US
    Posts
    123

    First and second derivatives

    Howdy, just a quick question,

    y = 4x/(square root (x+1)

    I have to find y' and y''

    I have this as my y'

    4(square root(x+1) - 2x/(square root x+1) all of this divided by x+1

    I can show my work if you want but it's just tedious writing it out on this, I can show it though if you like. (If my y' is wrong that is)
    My question is for y'' do I have to use product rule on the 4(square root x +1) then a quotient rule on 2x/( square root x+1) and then another quotient rule for the overall derivative? BLAH, I want to know if I'm over doing it or if it really is the right process.

    Thank you as always.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member
    Joined
    Jul 2012
    From
    INDIA
    Posts
    834
    Thanks
    209

    Re: First and second derivatives

    First and second derivatives-17-may-13.png
    Thanks from Oldspice1212
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member
    Joined
    Sep 2012
    From
    US
    Posts
    123

    Re: First and second derivatives

    How did you get Square root(x+10)?


    Edit: ah mistake for a parenthesis

    Shouldn't the denominator be just (x+1) since the square root gets cancelled out by 2​?
    Last edited by Oldspice1212; May 16th 2013 at 09:39 PM.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Super Member
    Joined
    Jul 2012
    From
    INDIA
    Posts
    834
    Thanks
    209

    Re: First and second derivatives

    You are absolutely right it is a typing error. It is sqrt ( x+1)
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Member
    Joined
    Sep 2012
    From
    US
    Posts
    123

    Re: First and second derivatives

    I'm still a bit confused on why the deno. is (x+1)^3/2 since it's g(x)^2 = (root x+1)^2 cancel out the root = x+1


    EDIT: I figured it out, I just had to do a bit more algebra, ty
    Last edited by Oldspice1212; May 16th 2013 at 10:23 PM.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 2
    Last Post: November 12th 2012, 01:55 AM
  2. Derivatives and Anti-Derivatives
    Posted in the Calculus Forum
    Replies: 7
    Last Post: February 6th 2011, 07:21 AM
  3. Replies: 1
    Last Post: July 19th 2010, 05:09 PM
  4. Replies: 4
    Last Post: February 10th 2009, 10:54 PM
  5. Trig derivatives/anti-derivatives
    Posted in the Calculus Forum
    Replies: 1
    Last Post: February 10th 2009, 02:34 PM

Search Tags


/mathhelpforum @mathhelpforum