Advertisement
If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie

F(b)-F(a)????????

Options
  • 27-08-2008 10:37pm
    #1
    straight_As
    Closed Accounts Posts: 193 ✭✭


    Guys,
    Once again I need your expert help.

    Can anyone offer me a proof as to why in the definite integral formula (integral sign)(limits (x=b, x=a)) f(x)dx = F(b)-F(a)

    I understand all the rest of the integration chapter but that's because I can prove it all. With this, it just seems to be a definition which is a bit boring and doesn't really allow me to understand where it comes from.

    PS I understand how integration is applied to area, it's just that I really don't like definitions.

    Thanks in advance.


Comments

  • Options
    #2
    PurpleFistMixer
    Registered Users Posts: 5,851 ✭✭✭PurpleFistMixer


    If you must know... Proof of the Second Fundamental Theorem of Calculus.

    I think it's easier to take it as "well, that's just how it is". (I know, bad maths practice to blindly accept, but at LC level there's only so many things you can handle the proofs of.)


  • Options
    #3
    Cokehead Mother
    Closed Accounts Posts: 773 ✭✭✭Cokehead Mother


    Here's a more LC-friendly "proof". It's not really a proof but it would have satisfied me this time last year.

    21kmsnd.gif


  • Options
    #4
    MathsManiac
    Registered Users Posts: 1,595 ✭✭✭MathsManiac


    That wikipedia proof (in PurpleFistMixer's message) might be a bit too formal for your taste, so you might prefer to scroll back up the article to the bit headed "geometric intuition". That may constitute enough of a proof to satisfy you. That, or a version of it, is often offered as a proof in less formal contexts.


  • Options
    #5
    timmywex
    Registered Users Posts: 2,626 ✭✭✭timmywex


    This all looks like double dutch to me, god i hate what summer has done to my maths!


  • Options
    #6
    Peleus
    Registered Users Posts: 784 ✭✭✭Peleus


    ye god. I got an A1 in maths and i can't remember any integration at this stage.


  • Advertisement
  • Options
    #7
    IrishKnight
    Registered Users Posts: 922 ✭✭✭IrishKnight


    Shameless joke;

    All the math functions, pi, phi, e, i, cos x, all of them were in a pub have a party. All of the functions where having great fun, apart from the number e, who was all alone at the bar.

    The barman came over and said, "Why don't you join your friends? They look like their having great fun."

    The number e replied, "I've tried, but I just can't integrate!"


  • Options
    #8
    Decerto
    Registered Users Posts: 309 ✭✭Decerto


    Peleus wrote: »
    ye god. I got an A1 in maths and i can't remember any integration at this stage.
    lol same and im starting a really maths intensive course next year


  • Options
    #9
    Peleus
    Registered Users Posts: 784 ✭✭✭Peleus


    Decerto wrote: »
    lol same and im starting a really maths intensive course next year

    ha, ye i'm doing engineering in trinity which apparently is mostly maths for the first two years


  • Options
    #10
    K4t
    Closed Accounts Posts: 6,362 ✭✭✭K4t


    This thread scares me :eek: :P


  • Options
    #11
    Davidius
    Registered Users Posts: 4,893 ✭✭✭Davidius


    When asked for proofs, just write down "'cause".

    A1 material.


  • Advertisement
Advertisement