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Logs/indices stuff

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Reply 20
Avatar for thefatone
thefatone
OP
6
Original post by LastMinReviseGuy
Who told you i had a big willy?
Sorry , but i don't.

pls... stahp
Original post by natninja
There are some core 4 papers where the A boundary is significantly higher. The one I say had an A boundary at 70 and the one the following January (yes this was way back in the past) had an A boundary of 71 and an A* boundary of 73...


these are ones from around 2005 to todays date
https://c4a3f001dcd45afe69d0ceec83003f9fbc283b2c.googledrive.com/host/0B1ZiqBksUHNYSGtmV3dzVVVvNTg/Grade%20Boundaries%20-%20Edexcel%20Maths%20A-level.pdf

i don't see any with those sort of boundaries for an A
Reply 21
Avatar for Zacken
Zacken
22
Original post by thefatone
pls... stahp


these are ones from around 2005 to todays date
https://c4a3f001dcd45afe69d0ceec83003f9fbc283b2c.googledrive.com/host/0B1ZiqBksUHNYSGtmV3dzVVVvNTg/Grade%20Boundaries%20-%20Edexcel%20Maths%20A-level.pdf

i don't see any with those sort of boundaries for an A


In your link, C4 Jan 11 it says it's 69 for an A.
Reply 22
Avatar for thefatone
thefatone
OP
6
Original post by Zacken
In your link, C4 Jan 11 it says it's 69 for an A.


O.O i seemed to have glanced over that one.... oh well...

can you help me with this actual logs question then?

given that
t=log3xt=log_3 x
find in terms of t

log3x2[br][br][br]log9xlog_3 x^2[br][br][br]log_9 x
(edited 7 years ago)
Original post by thefatone
O.O i seemed to have glanced over that one.... oh well...

can you help me with this actual logs question then?

given that
t=log3xt=log_3 x
find in terms of t

log3x2[br][br]log9xlog_3 x^2[br][br]log_9 x


Do you know that log⁡nxm=mlog⁡nx\log_nx^m=m\log_nx?

And that log⁡nx=log⁡mxlog⁡mn\log_nx=\dfrac{\log_mx}{\log_mn}?

And that log⁡nn=1\log_nn=1?
(edited 7 years ago)
Reply 24
Avatar for thefatone
thefatone
OP
6
Original post by Kvothe the arcane
Do you know that log⁡nxm=mlog⁡nx\log_nx^m=m\log_nx?

And that log⁡nx=log⁡mxlog⁡mn\log_nx=\dfrac{\log_mx}{\log_mn}?

And that log⁡nn=1\log_nn=1?


Ah thanks, i got the right answer but i'm not sure how i reached it xD
Original post by thefatone
Ah thanks, i got the right answer but i'm not sure how i reached it xD


Type out your working?
Reply 26
Avatar for thefatone
thefatone
OP
6
Original post by Kvothe the arcane
Type out your working?


ok so log9x=log3xlog39=log3x2=t2 log_9 x = \dfrac{log_3 x}{log_3 9} = \dfrac{log_3 x}{2}= \dfrac{t}{2}


next question is hence or otherwise find to 3 sig figs the value of x such that

log3x2−log9x=4log_3 x^2 - log_9 x = 4
Original post by thefatone
ok so log9x=log3xlog39=log3x2=t2 log_9 x = \dfrac{log_3 x}{log_3 9} = \dfrac{log_3 x}{2}= \dfrac{t}{2}


next question is hence or otherwise find to 3 sig figs the value of x such that

log3x2−log9x=4log_3 x^2 - log_9 x = 4


Your working above seems fine. Solve for t and then solve for x :h:.
Reply 28
Avatar for thefatone
thefatone
OP
6
Original post by Kvothe the arcane
Your working above seems fine. Solve for t and then solve for x :h:.


what if it said express

log32x log_3 2x

in terms of t how would i do this?
Reply 29
Avatar for Zacken
Zacken
22
Original post by thefatone
what if it said express

log32x log_3 2x

in terms of t how would i do this?


log⁡32+log⁡3x\log_3 2 + \log_3 x
Reply 30
Avatar for thefatone
thefatone
OP
6
Original post by Zacken
log⁡32+log⁡3x\log_3 2 + \log_3 x


thank you

but what if it says something like

log32x+1log_3 2x+1

what do i do then?
Reply 31
Avatar for Zacken
Zacken
22
Original post by thefatone
thank you

but what if it says something like

log32x+1log_3 2x+1

what do i do then?


What's the difference? 1+log⁡32+log⁡3x1 + \log_3 2 + \log_3 x
Reply 32
Avatar for thefatone
thefatone
OP
6
Original post by Zacken
What's the difference? 1+log⁡32+log⁡3x1 + \log_3 2 + \log_3 x


do the brackets make a difference?

log3(2x+1)log_3 \left(2x+1\right)?
Reply 33
Avatar for Zacken
Zacken
22
Original post by thefatone
do the brackets make a difference?

log3(2x+1)log_3 \left(2x+1\right)?


Yes, obviously so. In that case, it's not representable in terms of tt.
Reply 34
Avatar for thefatone
thefatone
OP
6
Original post by Zacken
Yes, obviously so. In that case, it's not representable in terms of tt.


is it not?

can't you just split it up? or does that not work?
Reply 35
Avatar for Zacken
Zacken
22
Original post by thefatone
is it not?

can't you just split it up? or does that not work?


How do you propose on splitting it up...?
Reply 36
Avatar for thefatone
thefatone
OP
6
Original post by Zacken
How do you propose on splitting it up...?


hmmm ah i see, the +1 inside with the 2x means you can't do anything about it :smile:
Reply 37
Avatar for Zacken
Zacken
22
Original post by thefatone
hmmm ah i see, the +1 inside with the 2x means you can't do anything about it :smile:


Yeah.

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