Results 1 to 4 of 4

Math Help - [SOLVED] Help with domain

  1. #1
    Member
    Joined
    Jul 2009
    Posts
    149

    [SOLVED] Help with domain

     f(x)=e^{-x^2}

    Find domain.
    Find first and second derivative

    Can some one please take me through this?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    12,134
    Thanks
    1013
    Quote Originally Posted by el123 View Post
     f(x)=e^{-x^2}

    Find domain.
    Find first and second derivative

    Can some one please take me through this?
    domain is all real numbers

    f'(x) = e^{-x^2} \cdot (-2x)

    f''(x) = e^{-x^2} \cdot (-2) + (-2x) \cdot e^{-x^2} \cdot (-2x)

    you can clean up the algebra
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Master Of Puppets
    pickslides's Avatar
    Joined
    Sep 2008
    From
    Melbourne
    Posts
    5,236
    Thanks
    29
    Quote Originally Posted by el123 View Post
     f(x)=e^{-x^2}

    Find domain.
    The function is defined for all values of x as you can square any real number and raise any real number over e.


    Quote Originally Posted by el123 View Post
     f(x)=e^{-x^2}


    Find first and second derivative
    Consider

    If y = e^{f(x)} \Rightarrow \frac{dy}{dx} = f'(x)e^{f(x)}

    to find the 1st.

    Repeat this in conjunction with the product rule on the 1st to obtain the second.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    ux0
    ux0 is offline
    Junior Member
    Joined
    Oct 2009
    Posts
    58
    Quote Originally Posted by el123 View Post
     f(x)=e^{-x^2}

    Find domain.
    Find first and second derivative

    Can some one please take me through this?
    The easiest way to understand domain is to ask yourself what values of X can i put into the function f(x)?

    The derivative is just

    e^udu

    where your

    u=-X^2

    <br />
f'(x)= -2xe^{-X^2}

    and ill leave you to find the second one, in which case you will have to use the chain rule...

    f(x)g(x)=f'(x)g(x)+f(x)g'(x)
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. [SOLVED] domain and range
    Posted in the Pre-Calculus Forum
    Replies: 2
    Last Post: March 13th 2009, 03:15 PM
  2. [SOLVED] Find the Domain: f(x) = 2e^(2 - x) + 1
    Posted in the Pre-Calculus Forum
    Replies: 3
    Last Post: February 4th 2009, 02:11 AM
  3. [SOLVED] Domain
    Posted in the Pre-Calculus Forum
    Replies: 15
    Last Post: September 23rd 2008, 09:21 PM
  4. [SOLVED] Domain and range
    Posted in the Algebra Forum
    Replies: 3
    Last Post: August 21st 2008, 10:05 PM
  5. [SOLVED] Domain
    Posted in the Math Topics Forum
    Replies: 1
    Last Post: November 15th 2005, 10:42 AM

Search Tags


/mathhelpforum @mathhelpforum