已知y=log3(4x x a-6),在[1,]-搜答案-神马作文网

设log3x=A易知—1≤A≤2对y=f(x)=log33x·log39x化简得f(x)=A×A+3A+2在[—1,2]单调递增,所以值域【0,12】很久没做过了,应该是这样吧!

根据对数函数的性质log(a)(M^n)=nlog(a)(M),log(a)(MN)=log(a)(M)+log(a)(N);所以,log3(8)-2log3(6)=log3（2的3次方）-2×（lo

x=2^3/3^(3/2)=4^(3/3)/3^(3/2)=3^(-3/3)/4^(-3/2)==(3/4)^(-3/2)所以原式=-3/2

log3(6)=log3(2×3)=log3(2)+log3(3)=log3(2)+1=lg2/lg3+1=a/b+1=(a+b)/b所以选第二个

1.4^x-10·2^x+16≤0设y=2^x则y^2-10y+16=

y=log3(x+3)log3(3x+9)=log3(x+3)*(log3(x+3)+1)=(log3(x+3))^2+log3(x+3)=(log3(x+3)+1/2)^2-1/4x²-2

[(x-y)/2]^2=xyx^2-2xy+y^2=4xyx^2-6xy+y^2=0(x/y)^2-6(x/y)+1=0x/y=3+2*2^0.5或者3-2*2^0.5

log3a1+log3a2+...+log3a8=log3[a1a2...a8]=log3[(a1a8)(a2a7)..(a4a5)]=log3[9^4)=log3(3^8)=8

log3（x+y）=log3(xy)所以xy=x+y所以（x-1）(y-1)=1又x,y是正整数所以x-1=1,y-1=1所以x=y=2所以x^y=4

因为log2[log3(log4x)]=0所以：log3(log4x)=1进一步：log4x=3所以x=4^3=64,.log3[log4(log2y)]=0则有：log4(log2y)=1进一步：l

log2[log4(log3x)]=0log4(log3x)=1log3x=4x=3^4=81同理log5(log2y)=1log2y=5y=32所以原式=4×9-2=34

已知函数y=(log3x)²-2log3x+3的定义域为[1,9],求函数的值域?令t=log3(x);则t∈[0,2]所以y=t²-2t+3=(t-1)²+2t=1时；

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/

log3为底数8对数-2log3为底数6对数=3log3为底数2的对数-2(log3为底数2的对数+1)=3a-2(a+1)=a-2;B正确

log38-2log36=a-log336=a-log34×9=a-2/3log38-log39=a-2a/3-2=a/3-2再问：log34乘以9=log34+log39吗再答：对

log3(4)=lg4/lg3=2lg2/lg3=2a/

f(x)=【log3(x+1)】/x=ln(x+1)/【x*ln3】换底公式,便于求导f'(x)=【x*ln3/(x+1)-ln3*ln(1+x)】/(x*ln3)^2=【x/(x+1)-ln(x+1

log36=lg6/lg3=(lg2+lg3)/lg3=(a+b)/b希望对您有所帮助

（1）x>0,y>0log3x+log3y=2log3(x-2y),log3(xy)=log3(x-2y)²xy=(x-2y)²x²-5xy+4y²=0(x-4