要使函数有意义必须：-1≤log0.5(3-x)≤2即：-1*log0.5(0.5)=-1≤log0.5(3-x)≤2=2*log0.5(0.5)log0.5(2)≤log0.5(3-x)≤log0.5(0.5²)因为函数log0.5(x)是减函数,所以2≥3-x≥1/4-2≤x-3≤-1/43-2≤x≤3-1/41≤...