Just one sec...
Hey! Sign in to get help with your study questionsNew here? Join for free to post

C3 Applications of Differentiation

Announcements Posted on
Take our short survey, £100 of Amazon vouchers to be won! 23-09-2016
    • Thread Starter
    Offline

    0
    ReputationRep:
    Name:  c3 2f.jpg
Views: 14
Size:  514.0 KBI am stuck on Q3,4,6,7,8,9,10,11 of the questions could anyone help? I have done Q1,2 &5.
    Online

    3
    ReputationRep:
    What exactly is it that you are unable to do?
    Offline

    0
    ReputationRep:
    Finding the coordinates mainly (found my old account hence the different username)
    Offline

    3
    ReputationRep:
    (Original post by henb99)
    Finding the coordinates mainly (found my old account hence the different username)
    (Original post by henbnyc)
    I am stuck on Q3,4,6,7,8,9,10,11 of the questions could anyone help? I have done Q1,2 &5.
    Q3 - I can't see what gradient the book shows to I'll just refer to it as m. Anyway, you have y=\frac{x}{1+x} so you need to find \frac{dy}{dx} by using an appropriate differentiation rule that you should know. Set \frac{dy}{dx}=m and solve for x to see at what x coordinates the gradient is m.

    Once you have your value(s) of x, plug them back through y=\frac{x}{1+x} to find your y coordinates.
    Online

    3
    ReputationRep:
    (Original post by henb99)
    Finding the coordinates mainly (found my old account hence the different username)
    It may be easier to differentiate  \frac{x}{1+x} if you express it in the form  1-\frac{1}{1+x} .
    Offline

    3
    ReputationRep:


    How do I solve? ^
    Offline

    3
    ReputationRep:
    (Original post by Aklaol)


    How do I solve? ^
    Create your own thread on the Maths forum and ask this. Don't hijack other threads, thanks.
    Offline

    0
    ReputationRep:
    (Original post by RDKGames)
    Q3 - I can't see what gradient the book shows to I'll just refer to it as m. Anyway, you have y=\frac{x}{1+x} so you need to find \frac{dy}{dx} by using an appropriate differentiation rule that you should know. Set \frac{dy}{dx}=m and solve for x to see at what x coordinates the gradient is m.

    Once you have your value(s) of x, plug them back through y=\frac{x}{1+x} to find your y coordinates.
    I have tried this but only get one set of coordinates instead of two

    When I differentiate using the quotient rule I get 1/(1+x)^2
    Offline

    3
    ReputationRep:
    (Original post by henb99)
    I have tried this but only get one set of coordinates instead of two

    When I differentiate using the quotient rule I get 1/(1+x)^2
    That's correct. When it comes to square rooting, you should get 2 solutions because x^2=a \Rightarrow x=\pm \sqrt{a}
    Offline

    0
    ReputationRep:
    (Original post by RDKGames)
    That's correct. When it comes to square rooting, you should get 2 solutions because x^2=a \Rightarrow x=\pm \sqrt{a}
    So the gradient 1/9 is equal to 1+x^-2

    -8/9=x^-2
    Offline

    1
    ReputationRep:
    (Original post by RDKGames)
    Create your own thread on the Maths forum and ask this. Don't hijack other threads, thanks.
    Lmao you look like a killjoy and you sure are
    Offline

    3
    ReputationRep:
    (Original post by henb99)
    So the gradient 1/9 is equal to 1+x^-2

    -8/9=x^-2
    Nope. So then \frac{1}{9}=(1+x)^{-2} \Rightarrow 9=(1+x)^2 \Rightarrow \pm 3 = 1+x
    Offline

    3
    ReputationRep:
    (Original post by BluntBluster)
    Lmao you look like a killjoy and you sure are
    Oh definitely a lot of joy posting complicated maths problems on a simple A-Level thread.
    Offline

    0
    ReputationRep:
    (Original post by RDKGames)
    Nope. So then \frac{1}{9}=(1+x)^{-2} \Rightarrow 9=(1+x)^2 \Rightarrow \pm 3 = 1+x
    Thank you so much I know how dumb I must sound, I have worked it out correctly

    For question 4, when I differentiated I got 3x(x+1)^2 which is equal to the gradient 7

    after this I got stuck again, there should only be one point (P)
    Offline

    3
    ReputationRep:
    (Original post by henb99)
    Thank you so much I know how dumb I must sound, I have worked it out correctly

    For question 4, when I differentiated I got 3x(x+1)^2 which is equal to the gradient 7

    after this I got stuck again, there should only be one point (P)
    Please state the original function, they are hard to see. Is it y=x(x-1)^3??? If so, check your differential again.
    Offline

    0
    ReputationRep:
    (Original post by RDKGames)
    Please state the original function, they are hard to see. Is it y=x(x-1)^3??? If so, check your differential again.
    My bad I had a plus instead of a minus
    I have got it to be (2,2)
    Offline

    3
    ReputationRep:
    (Original post by henb99)
    My bad I had a plus instead of a minus
    I have got it to be (2,2)
    Correct.
    Offline

    2
    ReputationRep:
    (Original post by RDKGames)
    Correct.
    What a levels to do btec level 3 ict with
 
 
 
Write a reply…

Reply

Submit reply

Register

Thanks for posting! You just need to create an account in order to submit the post
  1. this can't be left blank
    that username has been taken, please choose another Forgotten your password?
  2. this can't be left blank
    this email is already registered. Forgotten your password?
  3. this can't be left blank

    6 characters or longer with both numbers and letters is safer

  4. this can't be left empty
    your full birthday is required
  1. Oops, you need to agree to our Ts&Cs to register
  2. Slide to join now Processing…

Updated: September 18, 2016
TSR Support Team

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

Poll
Who will be the next permanent England boss?
Help with your A-levels

All the essentials

The adventure begins mug

Student life: what to expect

What it's really like going to uni

Rosette

Essay expert

Learn to write like a pro with our ultimate essay guide.

Uni match

Uni match

Our tool will help you find the perfect course for you

Study planner

Create a study plan

Get your head around what you need to do and when with the study planner tool.

Study planner

Resources by subject

Everything from mind maps to class notes.

Hands typing

Degrees without fees

Discover more about degree-level apprenticeships.

A student doing homework

Study tips from A* students

Students who got top grades in their A-levels share their secrets

Study help links and info

Can you help? Study help unanswered threadsRules and posting guidelines

Sponsored content:

HEAR

HEAR

Find out how a Higher Education Achievement Report can help you prove your achievements.

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

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