Results 1 to 5 of 5

Math Help - is this a "geometric formula" or calculus usage?

  1. #1
    Member
    Joined
    Sep 2008
    Posts
    126

    is this a "geometric formula" or calculus usage?

    use a geometric formula to evaluate the integral

    integral from 0 to 3

    (2x+1)dx

    I integrated the problem, getting x^2 + x

    Then I used the fundamental theorem of calculus, and I got 12-0 = 12..

    Did I use a geometric formula or just calculus?? If I used Calculus, how do I find the answer via geometric formula??
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor Mathstud28's Avatar
    Joined
    Mar 2008
    From
    Pennsylvania
    Posts
    3,641
    Quote Originally Posted by elpermic View Post
    use a geometric formula to evaluate the integral

    integral from 0 to 3

    (2x+1)dx

    I integrated the problem, getting x^2 + x

    Then I used the fundamental theorem of calculus, and I got 12-0 = 12..

    Did I use a geometric formula or just calculus?? If I used Calculus, how do I find the answer via geometric formula??
    The function f(x)=2x+1 on the interval [0,3] forms a triangle. Use that.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member
    Joined
    Sep 2008
    Posts
    126
    Ok, I did that.. Got A = {{1/2}}(3)(7) = {{21/2}}

    What am I doing wrong??
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor Mathstud28's Avatar
    Joined
    Mar 2008
    From
    Pennsylvania
    Posts
    3,641
    Quote Originally Posted by elpermic View Post
    Ok, I did that.. Got A = {{1/2}}(3)(7) = {{21/2}}

    What am I doing wrong??
    f(0)\ne{0}
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Member
    Joined
    Sep 2008
    Posts
    126
    I got it now..

    From [0, 3] it isn't a triangle, it's a trapezoid.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 3
    Last Post: October 17th 2011, 02:50 PM
  2. Replies: 1
    Last Post: September 16th 2011, 01:08 AM
  3. Replies: 2
    Last Post: April 24th 2011, 07:01 AM
  4. Replies: 1
    Last Post: October 25th 2010, 04:45 AM
  5. Replies: 1
    Last Post: June 4th 2010, 10:26 PM

Search Tags


/mathhelpforum @mathhelpforum