y=√lg[(5x-x²)/4]
①
lg[(5x-x²)/4]≥0
lg[(5x-x²)/4]≥lg1
(5x-x²)/4≥1
5x-x²≥4
x²-5x+4≤0
(x-1)(x-4)≤0
1≤x≤4
②
5x-x²＞0
x²-5x＜0
x(x-5)＜0
0＜x＜5
取①,②的交集得y的定义域[1,4]
如果这是原题y=lg√[(5x-x²)/4]
那么5x-x²＞0
x²-5x＜0
x(x-5)＜0
0＜x＜5
y的定义域(0,5)
请确认原题是哪个