比较下列4个数的大小
log1/2(5) log2(3) 1 3^-0.2
log2(3)>log2(2)=1
3^-0.2<3^0=1
log1/2(5)<log1/2(1)=0
所以log2(3)>1>3^-2>log1/2(5)