Question

设f(x)=log1/2[a^2x+2(ab)^x-3b^2x+1](a>0,b>0),解不等式f(x)＜0

Answer 1

log1/2[a^2x+2(ab)^x-3b^2x+1]＜0 ==> a^2x+2(ab)^x-3b^2x+1>1 ==> a^2x+2(ab)^x-3b^2x>0

化为 ((a/b)^x+3)((a/b)^x-1)>0 所以（a/b)^x>1=(a/b)^0

a>b时 ,x>0;a