2log以3为底2的对数-log以3为底32/9的对数+log以3为底8的对数-5的2倍log以5为底3的对数 =多少?
问题描述：
2log以3为底2的对数-log以3为底32/9的对数+log以3为底8的对数-5的2倍log以5为底3的对数 =多少?
答
2log3(2)-log3(32/9)+log3(8)-5*2*log5(3)
=log3(4)-log3(32/9)+log3(8)-5*2*log5(3)
=log3(4/(32/9))+log3(8)-5*2*log5(3)
=log3(4*9/32)+log3(8)-5*2*log5(3)
=log3(9/8)+log3(8)-5*2*log5(3)
=log3((9/8)*8)-5*2*log5(3)
=log3(9)-5*2*log5(3)
=log3(3^2)-10*log5(3)
=2-10*(log(3)/log(5))
=-4.826062