設3^x=4^y=12^z=a
則:
x=log3底 a=lga/lg3
y=log4底 a=lga/lg4
z=log12底a=lga/lg12
xy/(x+y)
=[(lga)^2/lg3lg4]/[lga(lg3+lg4)/lg3lg4]
=(lga)^2/(lga.lg12)
=lga/lg12
=z
得證.
代數(shù)題 3^X=4^Y=12^Z 證明Z=XY／X+Y
代數(shù)題 3^X=4^Y=12^Z 證明Z=XY／X+Y
數(shù)學比較差,大家多海涵……
數(shù)學比較差,大家多海涵……
數(shù)學人氣：899 ℃時間：2020-10-02 01:04:56
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