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

    22
    ReputationRep:
    (Original post by kiiten)
    if you have to determine if a point is maximum of minimum do you use the first or second derivative? Also, how do you know if it is max or min - is it +ve is max?
    When the first derivative is zero at a point, that point is a stationary point.

    When the second derivative is +ve at that point, the stationary point is a minimum.

    When the second derivative is -ve at that point, the stationary point is a maximum.
    • Thread Starter
    Offline

    17
    ReputationRep:
    (Original post by Zacken)
    When the first derivative is zero at a point, that point is a stationary point.

    When the second derivative is +ve at that point, the stationary point is a minimum.

    When the second derivative is -ve at that point, the stationary point is a maximum.
    Thank you!! - Does that apply for any other point on a curve?
    Offline

    22
    ReputationRep:
    (Original post by kiiten)
    Thank you!! - Does that apply for any other point on a curve?
    What d'you mean by that? It applies to any stationary point on a curve. A maximum or minimum has to be a stationary point.
    • Thread Starter
    Offline

    17
    ReputationRep:
    (Original post by Zacken)
    What d'you mean by that? It applies to any stationary point on a curve. A maximum or minimum has to be a stationary point.
    Oops sorry I forgot that a max/min point has to be stationary. Ignore the question
    • Thread Starter
    Offline

    17
    ReputationRep:
    2 separate cast circle question. Please could someone show me where i went wrong?
    Name:  1458593534493579759615.jpg
Views: 70
Size:  486.3 KBAttachment 514715514717
    Attached Images
     
    • Community Assistant
    • Study Helper
    Offline

    20
    ReputationRep:
    Community Assistant
    Study Helper
    (Original post by kiiten)
    2 separate cast circle question. Please could someone show me where i went wrong?
    Name:  1458593534493579759615.jpg
Views: 70
Size:  486.3 KBAttachment 514715514717
    1st one : Try expanding (3p+q)(p-2q). It's nearly correct.

    2nd one : It looks like you haven't performed any \sin^{-1}. You have used \sqrt{0.5} as your angle instead of \sin^{-1}\sqrt{0.5}.
    • Thread Starter
    Offline

    17
    ReputationRep:
    (Original post by notnek)
    1st one : Try expanding (3p+q)(p-2q). It's nearly correct.

    2nd one : It looks like you haven't performed any \sin^{-1}. You have used \sqrt{0.5} as your angle instead of \sin^{-1}\sqrt{0.5}.
    Thanks i got the 2nd one right now - ill try the 1st one later (did i get the +ve and -ve the wrong way round in the bracket?)

    Posted from TSR Mobile
    • Community Assistant
    • Study Helper
    Offline

    20
    ReputationRep:
    Community Assistant
    Study Helper
    (Original post by kiiten)
    Thanks i got the 2nd one right now - ill try the 1st one later (did i get the +ve and -ve the wrong way round in the bracket?)

    Posted from TSR Mobile
    Yes that was the mistake.
    • Thread Starter
    Offline

    17
    ReputationRep:
    How would the diagram look for this question?

    Name:  Screenshot 2016-03-29 15.28.09.png
Views: 52
Size:  11.8 KB
    • Thread Starter
    Offline

    17
    ReputationRep:
    I think this thread has died :'(
    Offline

    3
    ReputationRep:
    (Original post by kiiten)
    How would the diagram look for this question?

    Name:  Screenshot 2016-03-29 15.28.09.png
Views: 52
Size:  11.8 KB
    Zacken
    Offline

    22
    ReputationRep:
    (Original post by thefatone)
    Zacken
    The user has posted this in another thread.
    Offline

    3
    ReputationRep:
    (Original post by Zacken)
    The user has posted this in another thread.
    oh i see
 
 
 
  • 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.