a = ln(2)/ln(12)
[i just picked ln() for convenience ... works for log to any base]
need to show:
4a = (1-a)*log_6(16)
4*ln(2)/ln(12) =?= [1-ln(2)/ln(12)] * ln(16)/ln(6)
4*ln(2) =?= [ln(12) - ln(2)]*ln(2^4)/ln(6)
4*ln(2) =?= [ln(12) - ln(2)] * 4ln(2) / ln(6)
ln(6) =?= ln(12) - ln(2)
which is true since ln(a/b) = ln(a) - ln(b)
2007-11-28 17:21:24
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answer #1
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answered by halac 4
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i really dont see why you may have trouble, just use this rule, x = log base(y) z, then y^x = z, with the example you gave,
a = log(base 12)2, = 12^a = 2, so log(base 6)16=4a/(1-a) =
6^ (4a / 1-a) = 16, you already know what a is, so just evaluate a and plug into equation.
also to evaluate a in your calculator, just plug in log(2) / log (12) = a
2007-11-28 17:15:30
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answer #2
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answered by P 3
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a = log_12 2
Now
log_6 16 = log_6 (2^4) = 4 log_6 2
And
log_6 2 = log_12 2 / log_12 6
So
log_6 16 = 4 (log_12 2)/(log_12 6)
But
log_12 6 = log_12 (12/2) = log_12 12 - log_12(2) = 1 - log_12 (2)
so
log_6 16 = 4 (log_12 2)/(log_12 6)
= 4 (log_12 2)/(1 - log_12 2)
= 4a / (1-a)
QED
2007-11-28 17:43:58
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answer #3
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answered by PeterT 5
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a=log(base 12)2
=> 4a=4log(base6)2*log(base12)6
=> 4a=log(base6)16*[log(base12)12 - log(base12)2]
=> 4a=log(base6)16*(1 - a)
=> log(base6)16 = 4a / (1-a)
2007-11-28 17:32:39
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answer #4
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answered by Madhukar 7
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4a/(1-a)=log6(16)
4a=log6(16)-alog6(16)
4a+alog6(16)=log6(16)
a(4+log6(16)=log6(16)
a=log6(16)/[4+log6(16)]
log6(16)[(4+log6(16)]=log12(2)
log6(16)=4log12(2)+log6(16)log12(2)
log12(16)/log12(6)=log12(16)+log12(16)log12(2)/log12(6)
[log12(16))[1-log12(2)]/log12(6)=log12(16)
log12(16)[log12(12)-log12(2)]=log12(16)log12(6)
log12(16)log12(6)=log12(16)log12(6)
0=0
2007-11-28 17:21:44
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answer #5
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answered by someone2841 3
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