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

    13
    ReputationRep:
    Maybe its revision taking its toll or what, i dont know, but i cant seem to work out how the lecturer manipulated the first equation to change it to the second.



    http://i52.tinypic.com/1zacjn.jpg
    :confused:
    Offline

    14
    ReputationRep:
    He has done more than rearrange it, otherwise 1 / bracket in the first equation = the bracket in the second equation and that isn't true.

    Perhaps post in engineering or physics?
    • Thread Starter
    Offline

    13
    ReputationRep:
    (Original post by Ewan)
    He has done more than rearrange it, otherwise the bracket in the first equation = the bracket in the second equation and that isn't true.

    Perhaps post in engineering or physics?
    he must have, but unfortunately he just jumps from one eqn to the other.

    The thing is, the algebra leading up to those equations is very simple, but the bit in the image just threw me off completely
    Offline

    14
    ReputationRep:
    Well I don't even understand most of the words on the paper so can't help sorry :p:
    Offline

    0
    ReputationRep:
    this is just rearraging, just make sure you write out all the steps, otherwise it's hard to visualise.

    first of all, times by 4, then divde by V, then divide by the big bracket, ( or flip it and times it) now you have dR/R = (4Vo/V)(1+(dR/2R))

    now times the bracket, giving (4Vo/V) + (2VodR/Rv)

    then move the second term to the left:

    (dR/R)-(2VodR/Rv) = (4Vo/V)

    factorise:

    (dR/R)(1-2Vo/V) = (4Vo/V)

    then divide, to giving the answer shown on the screen

    (dR/R) = (4Vo/V)/(1-2Vo/V)
    • Thread Starter
    Offline

    13
    ReputationRep:
    thanks mate thats sorted it
    Offline

    0
    ReputationRep:
    no problem
 
 
 
  • 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 newspaper do you read/prefer?
    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.