If \(f(x)=\sqrt{x+4}+\sqrt{4-x}\), what is the domain of \(f\)?

Correct answer: \([-4,4]\)

For both square roots to be real, each radicand must be non-negative. From \(x+4\ge 0\), we get \(x\ge -4\), and from \(4-x\ge 0\), we get \(x\le 4\). Their intersection is \([-4,4]\), so option A is correct. Option B wrongly excludes \(-4\) and \(4\); at each endpoint, one square root is zero and the function is still defined. Exam tip: For several square roots, write a non-negative condition for every radicand and intersect the resulting sets.