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

    13
    ReputationRep:
    My maths teacher set us homework on mymaths and for the first part, we have to rearrange the equations into the form f(x)=0.
    One of the equations is In 2x = 3. I have never came across 'In' before, although I have seen it on calculators. How do you put this equation in the form f(x) = 0 and what on Earth is In and what are you supposed to do with it?
    Offline

    15
    ReputationRep:
     \ln x = \log_e x .
    The natural logarithm.
    You do not put it in f(x)=0 form.
    It's by definition. If  e^x=a \Rightarrow x=\ln a .
    Offline

    9
    ReputationRep:
    http://www.rapidtables.com/math/algebra/Ln.htm
    Offline

    11
    ReputationRep:
    ln is log base e. So similar if it was log base 10 on the left you'd make the right log10^3 and then remove logs from both sides.

    So ln2x=3
    ln2x=lne^3
    2x=e^3
    x=1/2(e^3)
    • Study Helper
    Offline

    16
    ReputationRep:
    Study Helper
    (Original post by jessyjellytot14)
    My maths teacher set us homework on mymaths and for the first part, we have to rearrange the equations into the form f(x)=0.
    One of the equations is In 2x = 3. I have never came across 'In' before, although I have seen it on calculators. How do you put this equation in the form f(x) = 0 and what on Earth is In and what are you supposed to do with it?
    If you just want to put it into the form f(x) = 0, then surely all you have to do is write

    ln(2x) - 3 = 0

    No?
    • Community Assistant
    • Welcome Squad
    Offline

    20
    ReputationRep:
    Community Assistant
    Welcome Squad
    It means L times by N times by 2x.
    Spoiler:
    Show
    Kappa
 
 
 
  • 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.