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

    9
    ReputationRep:
    (Original post by mbb123mbb)
    Wait. Inductive sequences? What do you mean? For C2 (and C1) we have arithmetic sequences and geometric sequences, and we need to know how to play around with those...but what are inductive sequences? Can't find them in the textbook.
    (I am doing Edexcel C2 by the way)
    I'm doing AQA, if it's not in your textbook then you probably don't have it in your spec
    Offline

    2
    ReputationRep:
    Got a question

    Log (base 3) XY = 5
    Log (Base 3) X Multiplied by Log (base 3) Y = 6,

    solve the simultaneus equation any ideas?
    Offline

    15
    ReputationRep:
    (Original post by SunDun111)
    Got a question

    Log (base 3) XY = 5
    Log (Base 3) X Multiplied by Log (base 3) Y = 6,

    solve the simultaneus equation any ideas?
    Split the first log up into the sum of 2 logs and then make a substitution of say  a= \log_3x and  b=\log_3y . Might make it easier to see.
    Offline

    2
    ReputationRep:
    If you have a question like 3^(2x-1) = 5, in aqa core 2 you can just use your calculator's log function to work it out i.e. log 3 5 = 2x-1?
    Offline

    2
    ReputationRep:
    (Original post by B_9710)
    Split the first log up into the sum of 2 logs and then make a substitution of say  a= \log_3x and  b=\log_3y . Might make it easier to see.
    cant do it still? can you expand
    Offline

    15
    ReputationRep:
    (Original post by SunDun111)
    cant do it still? can you expand
    So we have  \log_3x+\log_3y=5
    and  \log_3x \cdot \log_3y=6 .
    If we let  a=\log_3x and  b=\log_3y we get the simultaneous equations as

     a+b=5 and  ab=6 .
    You think you can take it from here?
    Offline

    2
    ReputationRep:
    (Original post by B_9710)
    So we have  \log_3x+\log_3y=5
    and  \log_3x \cdot \log_3y=6 .
    If we let  a=\log_3x and  b=\log_3y we get the simultaneous equations as

     a+b=5 and  ab=6 .
    You think you can take it from here?
    Yeah did it thanks!
    Offline

    0
    (Original post by RueXO)
    I'm doing AQA, if it's not in your textbook then you probably don't have it in your spec
    Yup, thought so, thank you
    Offline

    2
    ReputationRep:
    quick question guys, whenever they is a minus outside say for example .. - root 4, would the answer be minus 2?

    another question on that, if i have x^0.5 = -2, woul the answer be 4?
    • Thread Starter
    Offline

    4
    ReputationRep:
    Great to see everybody helping each other, really proud of everyone! Good luck tomorrow on core 2 guys, hopefully it will be a decent paper! We can then make an unofficial mark scheme tomorrow
    • Thread Starter
    Offline

    4
    ReputationRep:
    (Original post by SunDun111)
    quick question guys, whenever they is a minus outside say for example .. - root 4, would the answer be minus 2?

    another question on that, if i have x^0.5 = -2, woul the answer be 4?
    yes that is correct!
    Offline

    15
    ReputationRep:
    (Original post by SunDun111)
    quick question guys, whenever they is a minus outside say for example .. - root 4, would the answer be minus 2?

    another question on that, if i have x^0.5 = -2, woul the answer be 4?
     \sqrt{x} \geq 0 .
     \sqrt{x} \neq -2 .
    If you graph  y=\sqrt x then the range is  y \geq 0 .
    So  \sqrt x = -2 has no solutions.
    Offline

    2
    ReputationRep:
    On the spec for aqa it says that you should use mathematical notation in your working like the 'therefore' symbol. I've been using arrows to show the progression of my working but apparently the arrow means 'implies', so if I use symbols incorrectly but my working is still correct will I be ok?
    Offline

    0
    ReputationRep:
    In C2 for logarithms how do you manipulate a question with three minus logs??
    Coz I know that when there's a minus you divide the logs but how do you do that if there are three minuses??

    Ex: log(2)11x+3 - log(2)5x - 2log(2)x = 1
    Please help 😭😭😭
    Offline

    2
    ReputationRep:
    (Original post by B_9710)
     \sqrt{x} \geq 0 .
     \sqrt{x} \neq -2 .
    If you graph  y=\sqrt x then the range is  y \geq 0 .
    So  \sqrt x = -2 has no solutions.
    kinda confused me haha, so the square root of - 4 (when minus is on the outside) has no solutiosn?
    Offline

    2
    ReputationRep:
    (Original post by CrystalPark)
    In C2 for logarithms how do you manipulate a question with three minus logs??
    Coz I know that when there's a minus you divide the logs but how do you do that if there are three minuses??

    Ex: log(2)11x+3 - log(2)5x - 2log(2)x = 1
    Please help 😭😭😭
    take one of them to the other side, and turn the 1 into a log, so you get two logs on each side when they are all combines, so the logs cancel.
    Offline

    15
    ReputationRep:
    (Original post by SunDun111)
    kinda confused me haha, so the square root of - 4 (when minus is on the outside) has no solutiosn?
    That's not quite what i'm saying.  -\sqrt 4 =-2 and that's perfectly well defined.  \sqrt{-4} =2i which of course is not a real number. However you simply cannot have  \sqrt x =-2 . You can square both sides and get x=4, but putting x=4 into the square root returns 2, not -2. Taking the square root of a number never gives you a negative number.
    Offline

    0
    ReputationRep:
    (Original post by SunDun111)
    take one of them to the other side, and turn the 1 into a log, so you get two logs on each side when they are all combines, so the logs cancel.
    So would you turn 1 into log(2)2 and then cancel the logs??
    Does that work??
    Offline

    9
    ReputationRep:
    good luck everyone
    Offline

    1
    ReputationRep:
    How was it? Did anyone get a = 28, d = -2 and (2x - 5)(2x - 5) = 0 for the last question?
 
 
 
  • 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.