y=log(5底)(x+2)(x小于等于1)

∵x≤1∴x+2≤3
∵ x+2>0
∴0是x大于等于1不好意思我上面写错了y=log(5底)(x+2)(x≥1) ∵x≤1∴x+2≥3∴log(5底）(x+2)≥log(5底)3∴函数值域为[log(5)3,+∞)若是y=log(5底)(x）+2， (x≥1)log(5底)(x)≥0那么值域为[2.+∞)