✔ 最佳答案
Hello
Raising to 1/4 means take the square root of the square root.
You cannot take the square root of a negative number, it is not defined.
So, x² - 8x must be ≥ 0.
(x)(x - 8) ≥ 0
Make a short table
Between -inf and 0, x is negative. Over 0, it is positive
Between -inf and 8, x - 8 is negative. Over 8, it is positive
So, up to 0 both factors are negative ==> the product is positive
Between 0 and 8, x is positive, but x-8 negative ==> the product is negative
Over 8, both factors are positive ==> the product is positive
The function is defined when x ≤ 0 and when x ≥ 8.
Domain in interval notation : (-inf , 0] U [8, + inf)
Hope it helps
Bye !