Question

For \(f(x)=\frac{x-1}{x+1}\), what is the domain of \(f\circ f\)?

पर्याय

• \(\mathbb{R}-\{-1\}\)

• \(\mathbb{R}-\{0\}\)

• \(\mathbb{R}\)

• \(\mathbb{R}-\{-1,0\}\)

Answer 1

The input must satisfy \(x\neq-1\), and \(f(x)\) must also belong to the domain of \(f\), so \(f(x)\neq-1\). Solving gives \(x\neq0\), hence the domain is \(\mathbb{R}-\{-1,0\}\).