C4 formula HELP

Maths and statistics discussion, revision, exam and homework help.

Announcements Posted on
TSR launches Learn Together! - Our new subscription to help improve your learning 16-05-2013
IMPORTANT: You must wait until midnight (morning exams)/4.30AM (afternoon exams) to discuss Edexcel exams and until 1pm/6pm the following day for STEP and IB exams. Please read before posting, including for rules for practical and oral exams. 28-04-2013
Search Thread
Advanced Search
Sign in to Reply
  1. Crystal_Heart's Avatar
    1 20-06-2012  16:05
    • Junior Member
    C4 formula HELP
    Click image for larger version.  Name: formula1.JPG  Views: 34  Size: 13.1 KB  ID: 158727

    Found this in the C4 ocr spec, what does it mean and what's it for?

    Any help much appreciated, exam's tomorrow!
  2. supabof93's Avatar
    2 20-06-2012  16:11
    • New Member
    • Location: Milton Keynes
    • Posts: 17
    Re: C4 formula HELP
    I'm not familiar with that formula (I do Edexcel) but essentially what it looks like is that if you have a function x another function, and one of the functions contains the differential of the other, then it integrates like that
    Post rating:
    1
  3. aznkid66's Avatar
    3 20-06-2012  16:38
    • Exalted and Worshipped Member
    • Posts: 922
    Re: C4 formula HELP
    ...That's a formula? I don't recognize it either..

    Well, if you differentiate both sides, you get the chain rule, no?
    Maybe it's some form of
    Post rating:
    1
  4. james.h's Avatar
    4 20-06-2012  16:38
    • Benevolent Member
    • Posts: 698
    Re: C4 formula HELP
    It looks like just an application of the chain rule:

    \displaystyle \frac{\text{d}}{\text{d}x}(f(g(x )) = f'(g(x)) g'(x)

    Considering that (for "nice" functions) \int_a^b \frac{\text{d}}{\text{d}x}(f(x)) \ \text{d}x = f(b) - f(a), this then gives the formula you've quoted.


    An example of a question in which it may be of use:

    \displaystyle \text{Evaluate:\ }\int_0^{\pi} \sin(\sin(t)) \cos(t)\ \text{d}t

    Spoiler:
    Show
    Take f(t)=-\cos(t) and g(t)=\sin(t).

    Then use the formula. :yep:


    EDIT: In fairness, though, I can't see why it'd be any easier to use this formula than to do such integrals by substitution.
    Last edited by james.h; 20-06-2012 at 16:41.
    Post rating:
    1
  5. Crystal_Heart's Avatar
    5 20-06-2012  17:25
    • Junior Member
    Re: C4 formula HELP
    Thanks everybody for all your help.

    I think you're right and it's just a weird way of putting the chain rule. Just confused me cuz I'd never seen it before. Thanks for clearing that up.
Sign in to Reply
Search Thread
Advanced Search
Share this discussion:  
Useful resources

Articles:

Study Help rules and posting guidelinesStudy Help Member of the Month nominationsGuide to MathematicsMathematics resourcesMathematics websitesMathematics revision notes in the TSR wikiCambridge Assessment admissions tests (including STEP)How to use LaTeXCareers in Mathematics

Useful Dates:

Quick Link:

Unanswered Maths Threads

Groups associated with this forum:

View associated groups
Article updates
Moderators

We have a brilliant team of more than 60 volunteers looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is moderated by:

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22

Registered Office: International House, Queens Road, Brighton, BN1 3XE

Shortcuts

Get Started

TSR Group

Using TSR

Info

Connect with TSR

Reputation gems:
The Reputation gems seen here indicate how well reputed the user is, red gem indicate negative reputation and green indicates a good rep.
Post rating score:
These scores show if a post has been positively or negatively rated by our members.