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

    9
    ReputationRep:
    It's a question in one of the solomon papers. I have the answer but I don't understand how it comes to y=5/4?
    • Community Assistant
    Offline

    18
    ReputationRep:
    Community Assistant
    (Original post by funkybinoculars)
    It's a question in one of the solomon papers. I have the answer but I don't understand how it comes to y=5/4?
    Change it, so they're in the same base.
    Offline

    3
    ReputationRep:
    (Original post by funkybinoculars)
    It's a question in one of the solomon papers. I have the answer but I don't understand how it comes to y=5/4?
    log everything

    log(4)^y+1 + log(1) = log(8)^2y-1

    use log rules

    y+1log(4) + log(1) = 2y-1log(8)
    log 1 is zero so:
    y+1log(4) = 2y-1log(8)
    divide both sides by log(4) and 2y-1

    y+1/2y-1 = log(8)/log(4)
    y+1/2y-1 = 3/2

    multiply both sides by 2y-1 and 2
    2y+2 = 6y-3
    4y=5
    y=5/4
    • Thread Starter
    Offline

    9
    ReputationRep:
    (Original post by TheALevelStudent)
    log everything

    log(4)^y+1 + log(1) = log(8)^2y-1

    use log rules

    y+1log(4) + log(1) = 2y-1log(8)
    log 1 is zero so:
    y+1log(4) = 2y-1log(8)
    divide both sides by log(4) and 2y-1

    y+1/2y-1 = log(8)/log(4)
    y+1/2y-1 = 3/2

    multiply both sides by 2y-1 and 2
    2y+2 = 6y-3
    4y=5
    y=5/4
    yeah i thought about using log but don't know if i'd get a mark because we don't learn logs in c1?
    Offline

    3
    ReputationRep:
    (Original post by TheALevelStudent)
    log everything

    log(4)^y+1 + log(1) = log(8)^2y-1

    use log rules

    y+1log(4) + log(1) = 2y-1log(8)
    log 1 is zero so:
    y+1log(4) = 2y-1log(8)
    divide both sides by log(4) and 2y-1

    y+1/2y-1 = log(8)/log(4)
    y+1/2y-1 = 3/2

    multiply both sides by 2y-1 and 2
    2y+2 = 6y-3
    4y=5
    y=5/4
    No need. It is C1. Simple indices will resolve the issue here.

    (Original post by funkybinoculars)
    It's a question in one of the solomon papers. I have the answer but I don't understand how it comes to y=5/4?
    Consider:

     2^x = 2^3

    It shouldn't be difficult to see that x must be 3, because otherwise the sides won't be equal.

    In the case of

     4^{y+1}= 8^{2y-1}

    Consider what base 4 and 8 have in common and convert both of them to that base, i.e if I had 9 I could write it as 3^2.

    Once you have the same base, you know that you powers have to be the same (otherwise you won't have equality).

    Can you go from here?
    Offline

    3
    ReputationRep:
    (Original post by funkybinoculars)
    yeah i thought about using log but don't know if i'd get a mark because we don't learn logs in c1?
    (Original post by kingaaran)
    no need. It is c1. Simple indices will resolve the issue here.
    log everything
    Offline

    3
    ReputationRep:
    (Original post by TheALevelStudent)
    log everything
    Better get memorising log tables for your C1 exam then
    Offline

    3
    ReputationRep:
    (Original post by kingaaran)
    Better get memorising log tables for your C1 exam then
    Lmao, I'm doing A2, so there is no need. In A2 we log everything 😂😂
    Offline

    3
    ReputationRep:
    (Original post by TheALevelStudent)
    Lmao, I'm doing A2, so there is no need. In A2 we log everything 😂😂
    Log (everything) = life
    Offline

    3
    ReputationRep:
    (Original post by kingaaran)
    Log (everything) = life
    You know it haha 😂😂
 
 
 
  • 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
    Has a teacher ever helped you cheat?
    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
  • 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

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