Question

Find the domain of the function algebraically q(r)=3square root r^2 -16

Answer 1

hello :
q(r)=3√(r²-16)
q exist : r² - 16 ≥ 0
r² ≥ 16
√r² ≥ √16
but : √16 = 4 and √r² = |r |
|r | ≥ 4
r ≤ 4 or r ≥ 4
the domain is : ] -∞, 4] ∪ [,4 , + ∞ [