方程log2(x 3)-log4 x²
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原式=log2(12)-(1/2)log2(9)=log2(12)-log2(3)=log2(4)=2
对数方程log2(x-1)=log4x化为log2(x-1)=½log2x2log2(x-1)=log2xlog2(x-1)²=log2x(x-1)²=X接下去解二次方程
log2^(x-1)=log4^x则log2^(x-1)=log4^(x-1)²=log4^x则(x-1)²=x所以x²-3x+1=0则x=(3士√5)/2再问:log2
log4(3*2^x+7)=log2(2^x+1)lg(3*2^x+7)/lg4=lg﹙2^x+1)/lg2lg(3*2^x+7)/2lg2=lg﹙2^x+1)/lg2lg(3*2^x+7)/2=lg
log2(2x)=log2(x)+1log4(16x²)=log4(16)+log4(x²)=2+log2(x)令log2(x)=t,则原方程化为:(t+1)(t+2)=6即:t&
log2^x=log4^9=log2^2(3^2)=log2^3所以x=3
如果log4(log2^x)是表示外面的log以4为底,而里面的log以10或其它数(>0)为底的话,则log4(log2^x)=[log2(log2^x)]/2=log2(log4^x)=log2(
log2(2x)=lg(2x)/lg2log4(x/4)=lg(x/4)/lg4所以lg(2x)/lg2*lg(x/4)/lg4=2(lgx+lg2)/lg2*(lgx-2lg2)/(2lg2)=2再
log425=log2^25^2根据公式,m/nlogab=loga^nb^m所以,log425=log25明白了不?
log2(x-1)=log4x,则x>1log2(x-1)=log2√xx-1=√x(x-1)²=x
先换成同底的log4(2-x)=log4(x-1)^2-log44化简一下log4(2-x)=log4[(x-1)^2/4]然后2-x=(x-1)^2/4结果是x=2或-42舍掉(因为真数是0)-4也
log2(x^2-3)=2log4(6x-10)-1=》log2(x^2-3)=log4(6x-10)^2-1=>log2(x^2-3)=log2(6x-10)-1=》log2(x^2-3)=log2
log2(x-1)-log4(x+2)+1=0(x-1)^2/(x+2)=1/4整理,得X^2-2.25x+1.5=0得,X=0.25或2检验,得X=0.25不符合题意,X=2符合题意所以,X=2
答案:8其中2log4(x)=2/2log2(x)=log2(x);log8(x)=1/3log2(x).所以原式=(1+1+1/3)log2(x)=3/7log2(x)=7.所以log2(x)=3,
∵log2(x+1)2+log4(x+1)=5,∴log4(x+1)4+log4(x+1)=5,∴log4(x+1)5=5,∴(x+1)5=45,∴x=3.故答案为:3.
log2(3-x)-log4(x+5)=1log2(3-x)=1+log4(x+5)log4(3-x)²=log44(x+5)(3-x)²=4(x+5)x²-6x+9=4
记t=log2(x)则log4(2x)=log2(2x)/log2(4)=(1+t)/2则方程化为:t^2+(1+t)/2=22t^2+t-3=0(2t+3)(t-1)=0t=-3/2,1因此x=2^
∵方程log2(x-1)=log4(3-x),∴令f(x)=log2(x-1),g(x)=log4(3-x),分别画出f(x)和g(x)的图象,交点即为解集,交点为(2,0),∴方程的解集为{2},故
log2[log3(log4(x))]=0log3(log4(x))=1log4(x)=3x=4^3=64
=lg243/lg4-lg729/lg8=5lg3/2lg2-6lg3/3lg2=5lg3/2lg2-4lg3/2lg2=lg3/lg4=log4(3)原式=lg12/lg4-lg6/lg2=(2lg