2^(x-1)-(1/4)^x<02^(x-1)<(1/4)^x2^(x-1)<2^(-2x)(x-1)<-2x{x|x<1/3}
2^(x-1)-2^(-2x)<0 2^(x-1)<2^(-2x)其中y=2^x为增函数则 x-1<-2x 则 x<1/3
