函数f(x)=log(1/3)(-x^2+2x+2)的值域为
问题描述：
函数f(x)=log(1/3)(-x^2+2x+2)的值域为
答
-x^2+2x+2≤1,又因为在对数函数里,-x^2+2x+2＞0,∴log(1/3)(0)＜log(1/3)(-x^2+2x+2)≤log(1/3)(1),故-∞＜f（x）≤0,即≤0
函数f(x)=log(1/3)(-x^2+2x+2)的值域为
-x^2+2x+2≤1,又因为在对数函数里,-x^2+2x+2＞0,∴log(1/3)(0)＜log(1/3)(-x^2+2x+2)≤log(1/3)(1),故-∞＜f（x）≤0,即≤0