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logarithms

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Source: — Data Sufficiency |

by mathbyvemuri » Thu May 10, 2012 4:41 am
a2+b2 = 7ab
=> a2+b2+2ab = 9ab
=> (a+b)^2 = 9ab
Taking square root on both sides,
(a+b) = 3sqrt(ab)
=>1/3(a+b) = sqrt(ab)
take log on both sides,
log[1/3(a+b)] = 1/2(loga+logb)
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by Brent@GMATPrepNow » Thu May 10, 2012 5:48 am
Vookeh dyzynah wrote:If a2+b2 = 7ab show that
Log[1/3(a+b)]=1/2(log a+log b).
Logarithms and a proof? We've strayed a lonnnnnnng way from GMAT-land!

"Toto, I have a feeling we're not in Kansas anymore" :-)

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
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