Find the domain

Question

r(s)=2x+squareroot of x²-1

Answer 1

r(s)=2x+√ x²-1

to find the domain , look to what is inside the square root, the restriction here is that the value under the square root must be zero or positive,

x²-1 ≥ 0

x² ≥ 1

-1 ≥ x ≥ 1

so the domain is

D: ( ∞ , -1] U [ 1, ∞ )

Answer 2

x ∈ {x | x > 0}