The Student Room Group
Uni students - Complete our survey >>
Uni students - Complete our survey >>
Uni students - Complete our survey >>

AS Logarithms problem - C2

Scroll to see replies

Anyone who doesn't have one should really buy one, they are only about 10 pounds each on amazon. Although be careful, certain calculators aren't allowed and you should really check the models on edexcel.
look at page 14 of this document for full details
http://www.jcq.org.uk/attachments/published/898/2.%20ICE%2009-10.pdf
As others have said, just a little mistake, all the working is correct.
Reply 22
Avatar for Wilko94
Wilko94
OP
6
Guess what - 2 more problems I can't solve :frown:

Find the values of x for which:

log3x+2logx3=3 log_3x + 2log_x3 = 3

I've converted them both into base 10 (I think)

logxlog3+2log3logx=3 \dfrac{logx}{log3} + 2\dfrac {log3}{logx} = 3

:confused:
(edited 13 years ago)
Reply 23
Avatar for Wilko94
Wilko94
OP
6
Original post by Scottishsiv
Anyone who doesn't have one should really buy one, they are only about 10 pounds each on amazon. Although be careful, certain calculators aren't allowed and you should really check the models on edexcel.
look at page 14 of this document for full details
http://www.jcq.org.uk/attachments/published/898/2.%20ICE%2009-10.pdf


I have fx-83 - how do I do this?!
Reply 24
Avatar for Kareir
Kareir
2
Original post by Wilko94
Guess what - 2 more problems I can't solve :frown:

Find the values of x for which:

log3x+2logx3=3 log_3x + 2log_x3 = 3

I've converted them both into base 10 (I think)

logxlog3+2log3logx=3 \dfrac{logx}{log3} + 2\dfrac {log3}{logx} = 3

:confused:



dont forget your log rules...

log3x+2logx3=3 log_3x + 2log_x3 = 3

log3x+logx(32)=3 log_3x + log_x(3^2) = 3

logxlog3+log9logx=3 \dfrac{logx}{log3} +\dfrac {log9}{logx} = 3

which would be ( i think)

logx3+log9x=3 log\dfrac {x}{3} + log\dfrac {9}{x} = 3

Could be mistaken, though?
does anyone know how to do this equation
2logx=log4 + log (2x+5)
Original post by Wilko94
I have fx-83 - how do I do this?!


It is the button underneath the on button, one that says log. The first box you input the base and in the second you input the output.

so for example

3^2 = 9

So all you do is you input log to base three with an output of 9 and then you should get two as the answer. Just to make sure, does your calculator look like the one in the link shown?

http://www.google.co.uk/imgres?imgurl=http://www.comparestoreprices.co.uk/images/ca/casio-fx83es.jpg&imgrefurl=http://www.comparestoreprices.co.uk/calculators/casio-fx83es.asp&usg=__tVMS6T-HpCsKG-QXgUM6Q9Yz8sQ=&h=300&w=250&sz=10&hl=en&start=0&zoom=1&tbnid=ciSqH_4lSfJu7M:&tbnh=135&tbnw=113&ei=RVuKTfhNjbqEB7OlocgN&prev=/images%3Fq%3Dcasio%2Bfx-83%26um%3D1%26hl%3Den%26client%3Dfirefox-a%26sa%3DN%26rls%3Dorg.mozilla:en-GB:redface:fficial%26channel%3Ds%26biw%3D1366%26bih%3D549%26tbs%3Disch:1&um=1&itbs=1&iact=rc&dur=902&oei=RVuKTfhNjbqEB7OlocgN&page=1&ndsp=18&ved=1t:429,r:2,s:0&tx=59&ty=29
Reply 27
Avatar for Kareir
Kareir
2
Original post by princess271
does anyone know how to do this equation
2logx=log4 + log (2x+5)


Have you done anything on it?

these may help:

alogx=logxa[br]loga+logb=logab[br]loga−logb=logab alog x = log x^a[br]log a + log b = log ab[br]log a - log b = log \dfrac{a}{b}


_Kar.
Reply 28
Avatar for cj_134
cj_134
9
Original post by Wilko94
Guess what - 2 more problems I can't solve :frown:

Find the values of x for which:

log3x+2logx3=3 log_3x + 2log_x3 = 3

I've converted them both into base 10 (I think)

logxlog3+2log3logx=3 \dfrac{logx}{log3} + 2\dfrac {log3}{logx} = 3

:confused:


That answers comes out beautifully however the working is long...if you get to the end the answers are x=3 and x=9 , very nice question bro!
Reply 29
Avatar for daph123
daph123
Original post by Scottishsiv

Original post by Scottishsiv
Anyone who doesn't have one should really buy one, they are only about 10 pounds each on amazon. Although be careful, certain calculators aren't allowed and you should really check the models on edexcel.
look at page 14 of this document for full details
http://www.jcq.org.uk/attachments/published/898/2.%20ICE%2009-10.pdf


hi, just pass by and dropping a msg here. Does my casio fx-9860gii sd allowed in edexcel exam board?

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you