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+5
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avatar+9673 

\(\text{Given that }a=\log\left(1+\frac{1}{3}\right)\space\text{and}\space b=\log\left(1+\frac{1}{9}\right), \\\text{express log 2 and log 3 in terms of a and b.}\)

 Jul 18, 2016

Best Answer 

 #1
avatar+33661 
+10

Can also write 

 

a = log(4/3) → log4 - log3 → log(2^2) - log3 → 2log2 - log3

 

and

 

b = log(10/9) → log10 - log9 → 1 - log(3^2) → 1 - 2log3.  (I'm assuming log is log to base 10)

 

From these you should be able to rearrange to get log2 and log3 in terms of a and b.

 Jul 18, 2016
 #1
avatar+33661 
+10
Best Answer

Can also write 

 

a = log(4/3) → log4 - log3 → log(2^2) - log3 → 2log2 - log3

 

and

 

b = log(10/9) → log10 - log9 → 1 - log(3^2) → 1 - 2log3.  (I'm assuming log is log to base 10)

 

From these you should be able to rearrange to get log2 and log3 in terms of a and b.

Alan Jul 18, 2016
 #2
avatar+129852 
+5

For the first one, we have

 

a =  log ( 1 + 1/3)   →  log (4/3)    →   log (4) - log (3)   →  log(2^2) - log (3)  =  2log 2 - log (3)

 

Add  log(3) to both sides

 

a + log(3) =  2log(2)    

 

Divide both sides by 2

 

[ a + log (3) ] / 2    = log (2)

 

 

For the second we have

 

b = log (1 + 1/9)   →  log(10/9)  →  log (10) - log (9)  →    1 - log(3^2)   →   1 - 2log(3)

 

Add 2log(3)  to both sides  and subtract b from both sides

 

2log(3) =  1 - b      divide both sides by 2

 

log (3)   = [ 1 - b ] / 2

 

 

 

cool cool cool

 

 

 

cool cool cool

 Jul 18, 2016

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