Hey there! Sign in to join this conversationNew here? Join for free
x Turn on thread page Beta
    • Thread Starter
    Offline

    0
    ReputationRep:
    Hi everyone, can you help me with some A Level Core 3 OCR (non-MEI) questions please? They’re from the June 2010 paper. Here’s the link:
    http://www.ocr.org.uk/Images/65003-q...hematics-3.pdf

    The questions that I’m stuck on are 7) (according to the mark scheme I have to differentiate at some point, but I don't understand why?), 8) ii)b) and 9) iv). I’ve got the mark scheme to hand but I’m a bit muddled as to which methods to use to solve these problems. Can somebody please talk me through them step by step, showing me what I need to do, please. Thank you.
    Offline

    11
    ReputationRep:
    (Original post by Mr Cosine)
    Hi everyone, can you help me with some A Level Core 3 OCR (non-MEI) questions please? They’re from the June 2010 paper. Here’s the link:
    http://www.ocr.org.uk/Images/65003-q...hematics-3.pdf

    The questions that I’m stuck on are 7) (according to the mark scheme I have to differentiate at some point, but I don't understand why?), 8) ii)b) and 9) iv). I’ve got the mark scheme to hand but I’m a bit muddled as to which methods to use to solve these problems. Can somebody please talk me through them step by step, showing me what I need to do, please. Thank you.
    For 7. You need to find the area under the curve between P and where it touched the X axis. And from that take away the area under the line between P and where it meets the X axis, Q.

    You need to differentiate to find the equation of the line. You know the line is a tangent to the curve when x = 1. So if you differentiate the curve and sub in x = 1, you'll get the gradient of the line.

    For the bit on 8, write out T(3x) as 8/(Rcos(3x - alpha)) = 8/6 x (root 6)

    Now rearrange till you get cos(3x - alpha) = [SOMETHING]

    Then do inverse cos to get 3x - alpha = arccos([SOMETHING])

    Rearrange to find x. Draw the graph of cos and sketch that angle, and make sure the x is the smallest angle which it holds that value.

    For 9) You know a = -1, so you can sub in g(x) into f(x) and then you'll have a quadratic which you can solve for b.
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by SamKeene)
    For 7. You need to find the area under the curve between P and where it touched the X axis. And from that take away the area under the line between P and where it meets the X axis, Q.

    You need to differentiate to find the equation of the line. You know the line is a tangent to the curve when x = 1. So if you differentiate the curve and sub in x = 1, you'll get the gradient of the line.

    For the bit on 8, write out T(3x) as 8/(Rcos(3x - alpha)) = 8/6 x (root 6)

    Now rearrange till you get cos(3x - alpha) = [SOMETHING]

    Then do inverse cos to get 3x - alpha = arccos([SOMETHING])

    Rearrange to find x. Draw the graph of cos and sketch that angle, and make sure the x is the smallest angle which it holds that value.

    For 9) You know a = -1, so you can sub in g(x) into f(x) and then you'll have a quadratic which you can solve for b.
    OK, thanks for all your help! I really appreciate it I can do these problems now
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: January 21, 2014
Poll
Do you agree with the proposed ban on plastic straws and cotton buds?
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

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

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