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

    0
    ReputationRep:
    Ok heres the question paper:

    http://www.scribd.com/doc/16015592/E...question-paper

    Heres the markscheme;

    http://www.wimbledoncollege.org.uk/T...%2006%20MS.pdf

    I just don't understand 7b whatsoever, can 't get my head around it
    any help would be very much appreciated!
    Offline

    17
    ReputationRep:
    (Original post by guitarmike456)
    Ok heres the question paper:

    http://www.scribd.com/doc/16015592/E...question-paper

    Heres the markscheme;

    http://www.wimbledoncollege.org.uk/T...%2006%20MS.pdf

    I just don't understand 7b whatsoever, can 't get my head around it
    any help would be very much appreciated!
    There isn't too much to understand. It just wants you to rearrange the first expression to get sin2x=cos2x USING the results from part (a). Post some working and we'll tell you if you make a mistake.
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by Farhan.Hanif93)
    There isn't too much to understand. It just wants you to rearrange the first expression to get sin2x=cos2x USING the results from part (a). Post some working and we'll tell you if you make a mistake.
    I really don't follow, how can you get sin2x=cos2x from part A
    Offline

    17
    ReputationRep:
    (Original post by guitarmike456)
    I really don't follow, how can you get sin2x=cos2x from part A
    We're trying to go from:
    (1) \cos x \left(\dfrac{\cos 2x}{\sin x + \cos x}\right) = \dfrac{1}{2}

    to

    (2) \cos 2x = \sin 2x

    From part (a), you know that \frac{\cos 2x}{\cos x + \sin x} \equiv \cos x - \sin x and this term occurs in what we are given. So replace the fraction in (1) with cosx - sinx for a start to get:

    \cos x (\cos x - \sin x) = \frac{1}{2}.

    Now expand out the LHS. Does it look familiar? (take a look at your answer to part (b))
    • Thread Starter
    Offline

    0
    ReputationRep:
    AH i have it
    i feel foolish thanks!
 
 
 
  • 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
    Will you be richer or poorer than your parents?
    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.