- 对数方程已知log2=a,及log3=b以a及b写出下列各数：(
- 已知log2=a,及log3=b
以a及b写出下列各数：
(a)log12
(b)log(根号12)
若log(x+1)-log(x-1)=1,求x的值
化简：(4logx-logx^3)/log(x^0.5)
- (a)log12=log(2²×3)=log2²+log3=2log2+log3=2a+b
(b)log√12=log12^0.5=log12/2=(2a+b)/2=a+b/2
log(x+1)-log(x-1)=1
log[(x+1)/(x-1)]=log10
(x+1)/(x-1)=10
x+1=10(x-1)
9x=11
x=11/9
(4logx-logx³)/log√x
=(4logx-3logx)/logx^0.5
=logx/(1/2)logx
=2