Results 1 to 5 of 5

Math Help - [SOLVED] evaulating difinite integral???

  1. #1
    crb
    crb is offline
    Newbie
    Joined
    Jan 2008
    Posts
    24

    [SOLVED] evaulating difinite integral???

    Integrate [2xdx] from (1 to 2 )

    ans = x square ( from 1 to 2)

    evaulating from 1 to 2

    process 1 : x square from ( 1 to 2 ) = 2 square - 1 square = 3

    process 2: x square from ( 1 to 2 ) = [x*x ] from ( 1 to 2 )
    = (2-1)*(2-1) = 1*1 = 1

    which process is the correct one........really confused here????

    thanky u for helping
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member
    Joined
    Dec 2008
    From
    Scotland
    Posts
    901
    Quote Originally Posted by crb View Post
    Integrate [2xdx] from (1 to 2 )

    process 1 : x square from ( 1 to 2 ) = 2 square - 1 square = 3

    process 2: x square from ( 1 to 2 ) = [x*x ] from ( 1 to 2 )
    = (2-1)*(2-1) = 1*1 = 1

    which process is the correct one........really confused here????

    thanky u for helping
     \int_1^2 2xdx = [x^2]^2_1 = 2^2 - 1^2 = 4-1 = 3
    Follow Math Help Forum on Facebook and Google+

  3. #3
    crb
    crb is offline
    Newbie
    Joined
    Jan 2008
    Posts
    24
    thank u for helping out........but could u explain why the second one is incorrect?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,605
    Thanks
    1573
    Awards
    1
    Quote Originally Posted by crb View Post
    could u explain why the second one is incorrect?
    Consider this.
    \left. {\left( {x \cdot x} \right)} \right|_1^2  = \left( {2 \cdot 2} \right) - \left( {1 \cdot 1} \right) = 3
    Follow Math Help Forum on Facebook and Google+

  5. #5
    crb
    crb is offline
    Newbie
    Joined
    Jan 2008
    Posts
    24
    thank you...very much
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. evaulating integrals
    Posted in the Calculus Forum
    Replies: 4
    Last Post: February 27th 2010, 08:06 AM
  2. Evaulating Riemann Sums
    Posted in the Number Theory Forum
    Replies: 1
    Last Post: January 25th 2010, 06:34 AM
  3. Evaulating Riemann Summations
    Posted in the Number Theory Forum
    Replies: 7
    Last Post: January 21st 2010, 07:05 PM
  4. Replies: 4
    Last Post: December 6th 2009, 02:51 PM
  5. Replies: 2
    Last Post: December 6th 2009, 12:56 PM

Search Tags


/mathhelpforum @mathhelpforum