Find the domain of f(x)=-sqrtx^2-16
The square root of a negative number is not a real number. Therefore, for the function f(x)=-√(x^2-16) to be defined, the expression inside the square root must be greater than or equal to 0.
x^2 - 16 ≥ 0
x^2 ≥ 16
x ≥ ±4
The domain of the function f(x)=-√(x^2-16) is all real numbers greater than or equal to 4 and less than or equal to -4. In interval notation, the domain is (-∞, -4] U [4, ∞).