Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

    0
    ReputationRep:
    I had a go at one C4 question paper today and and I came across this question no 6:


    http://www.school-portal.co.uk/Group...urceId=3992062

    Pls can you check if my working out is correct?
    *integral sign* t(t+1) (-2t) dt (ON TOP OF *integral sign* I HAD 0 AND ON BOTTOM ROOT 2)
    *integral sign* (-2t^3 -2t^2) dt
    [-2t^4/ 4 - 2t^3/ 3 ]

    Then subbing in 0 gave 0. so 0- ({6+4sqrt2}/ 3)

    I am asking if my method is OK because the MS is doing something different , they are removing the - sign and when they do this they are swapping the limits around?
    • PS Helper
    • Study Helper
    Offline

    13
    ReputationRep:
    PS Helper
    Study Helper
    It would be great if you could use LaTeX to write out maths.
    You need a positive area, because it's an area. The reason you swap the limits is:
    \int_a^b f = -\int_b^a f, because it's a useful convention that works.
    Offline

    3
    ReputationRep:
    (Original post by laurawoods)
    I had a go at one C4 question paper today and and I came across this question no 6:


    http://www.school-portal.co.uk/Group...urceId=3992062

    Pls can you check if my working out is correct?
    *integral sign* t(t+1) (-2t) dt (ON TOP OF *integral sign* I HAD 0 AND ON BOTTOM ROOT 2)
    *integral sign* (-2t^3 -2t^2) dt
    [-2t^4/ 4 - 2t^3/ 3 ]

    Then subbing in 0 gave 0. so 0- ({6+4sqrt2}/ 3)
    [
    Your correct substitution would be

    0-((-6-4sqrt2)/3)=\frac{6+4\sqrt{2}}{3}
 
 
 
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • Poll
    What's your favourite Christmas sweets?
    Useful resources

    Make your revision easier

    Maths

    Maths Forum posting guidelines

    Not sure where to post? Read the updated guidelines here

    Equations

    How to use LaTex

    Writing equations the easy way

    Student revising

    Study habits of A* students

    Top tips from students who have already aced their exams

    Study Planner

    Create your own Study Planner

    Never miss a deadline again

    Polling station sign

    Thinking about a maths degree?

    Chat with other maths applicants

    Can you help? Study help unanswered threads

    Groups associated with this forum:

    View associated groups
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • 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

    Quick reply
    Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.