log3(2)和log4(3)用换底公式怎么比较呢
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发布时间:2024-09-28 18:50
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热心网友
时间:2024-10-21 09:50
解log3(2)-log4(3)
=lg(2)/lg(3)-lg(3)/lg(4)
=lg(2)lg(4)/lg(3)lg(4)-lg(3)lg(3)/lg(4)lg(3)
=[lg(2)lg(4)-lg(3)lg(3)]/lg(4)lg(3)
而lg(2)lg(4)/lg(3)lg(3)
=log3(2)log3(4)
≤[(log3(2)+log3(4))/2]^2
=[log3(8)/2]^2
<[log3(9)/2]^2
=1
即lg(2)lg(4)/lg(3)lg(3)<1
即lg(2)lg(4)<lg(3)lg(3)
即lg(2)lg(4)-lg(3)lg(3)<0
即[lg(2)lg(4)-lg(3)lg(3)]/lg(4)lg(3)<0
即log3(2)<log4(3)
热心网友
时间:2024-10-21 09:53
log3(2)=lg2/lg3
log4(2)=lg2/lg4
lg1=0<lg2<lg3<lg4
由于lg3<lg4所以lg2/lg3>lg2/lg4
即log3(2)>log4(2)