log2=a ,log3=b,求log34
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运用换底log14(56)=log3(56)/log3(14)=log3(7*8)/log3(2*7)=〔log3(7)+log3(8)〕/〔log3(7)+log3(2)〕log3(2)=1/log
log23=a;log37=b即lg3/lg2=a;lg7/lg3=b;所以lg7/lg2=a*b所以log72=1/a*b同理log142=1/1+ab;所以结果为(3+ab)/(1+ab)
log3底数4=log3/(2log2)=b/(2a)log2底数12=log2/log12=log2/(2log2+log3)=a/(2a+b)
运用换底:log14(56)=log3(56)/log3(14)=〔log3(7)+log3(8)〕/〔log3(7)+log3(2)〕log3(2)=1/log2(3)=1/alog3(8)=3lo
答:ab=log2^7ab+1=log2^7+1=log2^14ab+3=log2^7+3=log2^56log14^56=(ab+3)/(ab+1)
lg12=2lg2+lg3=2a+blg12^5=(2a+b)5
log14^56=log3^56/log3^14=(log3^7+3log3^2)/(log3^7+log3^2)=(b+3/a)/(b+1/a)=(3+ab)/(1+a)
若log23=a,log37=b则log23*log37=ab即log27=ablog1456=log214/(log256)=(log22*7)/(log27*8)=(log22+log27)/(l
log2(log0.5(log2a))=0log0.5(log2a)=1log2a=0.5a=平方根下2,log3(log1/3(log3b))=0log1/3(log3b)=1log3b=1/3b=
由lg2=a,lg3=b得log2(3)=b/a,log3(2)=a/b,所以log3(4)=2log3(2)=2a/blog2(12)=log2(4X3)=2+log2(3)=2+b/a再问:不太懂
运用换底:log14(56)=log3(56)/log3(14)=〔log3(7)+log3(8)〕/〔log3(7)+log3(2)〕log3(2)=1/log2(3)=1/alog3(8)=3lo
log1256=lg56/lg12=(3lg2+lg7)/(lg3+lg4)因为a=lg3/lg2所以lg3=alg2因为b=lg7/lg3所以lg7=blg3=ablg2所以原式=(3lg2+abl
a=lg3/lg2b=lg7/lg3log4256=lg56/lg42=(lg7+3lg2)/(lg2+lg3+lg7)=(lg7/lg3+3lg2/lg3)/(lg2/lg3+1+lg7/lg3)=
log(2)3=a==>lg3/lg2=a==>lg3=alg2log(3)5=b==>lg5/lg3=b==>lg5=blg3=ablg2log(15)20=lg20/lg15=(lg2+lg2+l
已知log210=a,换底公式1/lg2=alg2=1/alog310=b1/lg3=blg3=1/blog3(4)=lg4/lg3=2lg2/lg3=2b/a请参考……
log3(2)=lg2/lg3=a/blog3(4)=2log3(2)=2a/
a=lg3/lg2lg3=alg2b=lg7/lg3lg7=blg3=ablg2log42(56)=lg56/lg42=lg(2^3*7)/lg(2*3*7)=(3lg2+lg7)/(lg2+lg3+
(ab+3)/(1+ab+a)a=lg3/lg2lg3=alg2同理lg7=blg3=ablg2log45(56)=lg56/lg42={lg7+2lg2}/lg7+3lg2}带入约分得结果