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

    14
    ReputationRep:
    If you have say -ln(2-x) How would you sketch this in terms of translations. Is there any order in terms of which ones you do. I think I'm right in saying inside the bracket first but in this case we have a horizontal translation and a flip in the y axis? Its horizontal translation then a flip in the y then in the x i think but is there a rule for this kind of thing thanks.
    • TSR Support Team
    • Study Helper
    Offline

    20
    ReputationRep:
    (Original post by 111davey1)
    If you have say -ln(2-x) How would you sketch this in terms of translations. Is there any order in terms of which ones you do. I think I'm right in saying inside the bracket first but in this case we have a horizontal translation and a flip in the y axis?
    You need to be a bit careful here.

    If you start with \ln(-x) (which is a horizontal reflection of the ln graph) then you next need to get to \ln(2-x)

    If you say f(x) = \ln(-x) then f(x+2) = \ln(-(x+2)) = \ln(-x-2).

    So f(x+2) is not the correct transformation. Can you see what transformation you need instead?

    Then there's one last transformation that I haven't mentioned.
    • Thread Starter
    Online

    14
    ReputationRep:
    (Original post by notnek)
    You need to be a bit careful here.

    If you start with \ln(-x) (which is a horizontal reflection of the ln graph) then you next need to get to \ln(2-x)

    If you say f(x) = \ln(-x) then f(x+2) = \ln(-(x+2)) = \ln(-x-2).

    So f(x+2) is not the correct transformation. Can you see what transformation you need instead?

    Then there's one last transformation that I haven't mentioned.
    I think f(x-2)... so the correct way is to reflect then translate 2 to right
    ?
    • TSR Support Team
    • Study Helper
    Offline

    20
    ReputationRep:
    (Original post by 111davey1)
    I think f(x-2)... so the correct way is to reflect then translate 2 to right?
    Yes that's right. A very common mistake would be to say it's f(x+2) but you can see that it's not.

    There's one last reflection at the end to get -ln(2-x) from ln(2-x).
    • Thread Starter
    Online

    14
    ReputationRep:
    (Original post by notnek)
    Yes that's right. A very common mistake would be to say it's f(x+2) but you can see that it's not.

    There's one last reflection at the end to get -ln(2-x) from ln(2-x).
    Thank you
 
 
 
  • 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
    Did TEF Bronze Award affect your UCAS choices?
    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.