a=log以3为底2的对数,b=log以3为底5的对数,用a,b,表示log以27为底100的对数,

问题描述:

a=log以3为底2的对数,b=log以3为底5的对数,用a,b,表示log以27为底100的对数,

答:
a=log3(2),b=log3(5)
log27(100)
=log3(100)/log3(27)
=log3(10^2)/3
=2log3(10)/3
=(2/3)*[log3(2)+log3(5)]
=(2/3)*(a+b)
=2(a+b)/3