解对数函数的不等式.2log a (√(4-x))-log (√a)2≥2log a (x-1)注:log a x.是log以a为底x的对数.

问题描述:

解对数函数的不等式.
2log a (√(4-x))-log (√a)2≥2log a (x-1)
注:log a x.是log以a为底x的对数.

2log a (√(4-x))-log (√a)2≥2log a (x-1)
2log a (√(4-x))-log a4≥2log a (x-1)(4-x>0,x-1>0)
log a (4-x)-log a4≥log a (x-1)^2(1loga[(4-x)/4]≥log a (x-1)^2(1a>1时,[(4-x)/4]≥(x-1)^2(1a所以原不等式的解集是(1,4)

原式即证:2*1/2loga (4-x)-loga 4>=loga (x-1)^2 (1 即 loga (4-x)>=loga 4(x-1)^2 (1当a>1时,有4-x>=4(x-1)^2,4x^2-7x当0=0,x>=7/4或者x

将2log a (√(4-x))-log (√a)2≥2log a (x-1)化简为:log a (√(4-x)²)/4=log a(x-1)²4-x>0,x-1>0,1<x<41,.当0<a<1时,对数函数为减函数,(x-1)²>=(√(4-x)²)/4,解得x>=...

你的不等式等价于 (4-x)/4 >= (x-1)^2
7/4