Results 1 to 6 of 6

Math Help - Integrals using step functions

  1. #1
    Junior Member
    Joined
    May 2010
    Posts
    74

    Integrals using step functions

    I have the integral from 1 to 5 of [h(t-2) + h(t)]lnt dt

    I broke this integral into integral from 1 to 5 of [h(t-2)ln t] + integral from 1 to 5 of [h(t) lnt]

    but now I don't know how to actually use the step function to find the answer..
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by CookieC View Post
    I have the integral from 1 to 5 of [h(t-2) + h(t)]lnt dt

    I broke this integral into integral from 1 to 5 of [h(t-2)ln t] + integral from 1 to 5 of [h(t) lnt]

    but now I don't know how to actually use the step function to find the answer..
    Do you know the definition of the step function? If so, apply it to your problem ....
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    May 2010
    Posts
    74
    h(t - a) = 1 if t>= a and 0 if t<a ? but uumm how do i know what t is..? :S
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Junior Member
    Joined
    May 2010
    Posts
    74
    Wait is it because its bewteen 1 to 5?? so if its in between there we can say it is equal to 1 and if it is not then it is equal to 0?
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Junior Member
    Joined
    May 2010
    Posts
    74
    Actually I don't understand it..

    I have h(t-2) = 1 when t>=2 and 0 when t < 2

    With the integral from 1 to 5 of h(t-2)lnt do i do integral from 1 to 2 of lnt x 0 is equal to zero then plus integral from 2 to 5 of lnt x 1?
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by CookieC View Post
    Actually I don't understand it..

    I have h(t-2) = 1 when t>=2 and 0 when t < 2

    With the integral from 1 to 5 of h(t-2)lnt do i do integral from 1 to 2 of lnt x 0 is equal to zero then plus integral from 2 to 5 of lnt x 1?
    You will need to break up the interval of integration into subintervals and use the appropriate value of the step functions in each of those subintervals.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Integrals and Equations Involving Step Functions
    Posted in the Advanced Applied Math Forum
    Replies: 2
    Last Post: February 26th 2011, 02:11 PM
  2. Step Functions
    Posted in the Differential Geometry Forum
    Replies: 2
    Last Post: January 17th 2011, 05:14 AM
  3. Replies: 2
    Last Post: October 12th 2010, 12:51 PM
  4. Step Functions
    Posted in the Differential Equations Forum
    Replies: 2
    Last Post: April 14th 2010, 12:48 AM
  5. Step Functions
    Posted in the Calculus Forum
    Replies: 1
    Last Post: March 26th 2009, 06:54 AM

Search Tags


/mathhelpforum @mathhelpforum