y=log(5+4x-x^)的值域是 1/3

热心网友

y=log(5+4x-x^)的值域是0＜5+4x-x^=-(x^-4x+4)+9=-(x-2)^+9≤9∴当0＜底数＜时1，y=log(5+4x-x^)的值域是[log9,+∞)当底数＞1时，y=log(5+4x-x^)的值域是(-∞,log9]