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# Very quick question on logs

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1. Very quick question on logs
Rewrite the equation in the form where c and d are constants.

I've tried numerous things but nothing seems to work. Some hints would be appreciated.
2. Re: Very quick question on logs
Note that
3. Re: Very quick question on logs
xlog3 = (x+1)log2

xlog3 = xlog2 + log2

xlog3 - xlog2 = log2

Am I on the right lines?
4. Re: Very quick question on logs
I don't think you need logs to answer the question you've asked here OP
5. Re: Very quick question on logs
(Original post by nohomo)
I don't think you need logs to answer the question you've asked here OP
No, not really, but using natural logs I got it to
6. Re: Very quick question on logs
(Original post by Perpetuallity)
Rewrite the equation in the form where c and d are constants.

I've tried numerous things but nothing seems to work. Some hints would be appreciated.

=> 3^x = 2 X 2^x

Dividing both sides by 2^x

=> (3^x)/(2^x) =2

=> (3/2)^x =2

=> 1.5^x = 2

7. Re: Very quick question on logs
(Original post by Perpetuallity)
No, not really, but using natural logs I got it to
I think your method is overkill.
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8. Re: Very quick question on logs
(Original post by najinaji)
xlog3 = (x+1)log2

xlog3 = xlog2 + log2

xlog3 - xlog2 = log2

Am I on the right lines?
Then (Log rule)

Last edited by TheGrinningSkull; 17-05-2012 at 19:06.
9. Re: Very quick question on logs
(Original post by Perpetuallity)
No, not really, but using natural logs I got it to
Steve2005 explains a simpler way of answering the question.
10. Re: Very quick question on logs
(Original post by Perpetuallity)
No, not really, but using natural logs I got it to
Your 5.54 value should be 5,526...BUT no need to involve logs.
11. Re: Very quick question on logs
(Original post by steve2005)
Your 5.54 value should be 5,526...BUT no need to involve logs.
I know, I truncated (ln3-ln2) in my workings which carried through and changes the final answer slightly.
12. Re: Very quick question on logs
(Original post by steve2005)
I think your method is overkill.
I couldn't do it that way in an exam situation. I think I just don't know the indices rules to that level.

Oh wait, yes I do, normally we do it the other way round, multiply out the brackets, never tried that. nice...
Last edited by Pride; 17-05-2012 at 19:36.
13. Re: Very quick question on logs
(Original post by Perpetuallity)
I know, I truncated (ln3-ln2) in my workings which carried through and changes the final answer slightly.
I realise that is what you did BUT it is not correct to round as you progress through a calculation.

ROUNDING should only occur at the final answer stage.
14. Re: Very quick question on logs
(Original post by TheGrinningSkull)
Then (Log rule)

Excellent! Hoped that would be the right method.
15. Re: Very quick question on logs
(Original post by steve2005)
I realise that is what you did BUT it is not correct to round as you progress through a calculation.

ROUNDING should only occur at the final answer stage.
I'll use the "ans" button on the calculator next time. Thanks for the help.
16. Re: Very quick question on logs
(Original post by najinaji)
Excellent! Hoped that would be the right method.
Yea, it looks right, it makes sense as well, and then you can solve for x

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