Results 1 to 7 of 7

Math Help - How can I derivate this?

  1. #1
    Junior Member
    Joined
    Feb 2011
    Posts
    54

    How can I derivate this?

    e^{-x}}\sum _{k=0}^{2011}{\frac {{x}^{k}}{k!}
    Thank you!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor Siron's Avatar
    Joined
    Jul 2011
    From
    Norway
    Posts
    1,250
    Thanks
    20

    Re: How can I derivate this?

    Use the product rule and:
    \frac{d}{dx}\left(\sum_{k=0}^{2011} \frac{x^k}{k!}\right)=\sum_{k=0}^{2011} \frac{d}{dx}\left(\frac{x^k}{k!}\right)
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Feb 2011
    Posts
    54

    Re: How can I derivate this?

    OKay, but i dont know how to derivate that factorial stuff
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Master Of Puppets
    pickslides's Avatar
    Joined
    Sep 2008
    From
    Melbourne
    Posts
    5,236
    Thanks
    29

    Re: How can I derivate this?

    You are only taking the derivative with respect to x, k! is constant.
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Junior Member
    Joined
    Feb 2011
    Posts
    54

    Re: How can I derivate this?

    Then it is only kx^k-1 /k!?
    Follow Math Help Forum on Facebook and Google+

  6. #6
    -1
    e^(i*pi)'s Avatar
    Joined
    Feb 2009
    From
    West Midlands, England
    Posts
    3,053
    Thanks
    1

    Re: How can I derivate this?

    Quote Originally Posted by gotmejerry View Post
    Then it is only kx^k-1 /k!?
    \frac{kx^{k-1}}{k!} is correct, however, you can use your definition of a factorial to cancel a factor of k giving \dfrac{x^{k-1}}{(k-1)!}

    But don't forget your other term and use the product rule
    Follow Math Help Forum on Facebook and Google+

  7. #7
    Junior Member
    Joined
    Feb 2011
    Posts
    54

    Re: How can I derivate this?

    Thank you!
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Derivate
    Posted in the Calculus Forum
    Replies: 3
    Last Post: April 16th 2011, 07:30 AM
  2. Derivate
    Posted in the Calculus Forum
    Replies: 4
    Last Post: December 29th 2010, 05:55 PM
  3. [SOLVED] How to derivate these?
    Posted in the Calculus Forum
    Replies: 6
    Last Post: November 16th 2010, 02:56 PM
  4. How to derivate this one?
    Posted in the Calculus Forum
    Replies: 2
    Last Post: June 9th 2010, 07:00 PM
  5. Derivate.
    Posted in the Calculus Forum
    Replies: 10
    Last Post: July 6th 2006, 01:08 AM

Search Tags


/mathhelpforum @mathhelpforum