If $f(x)=\left\{\begin{array}{l}x^2 ; x \geq 0 \\ x ; x<0\end{array}\right.$, then fof (x) is :
Answer & explanation
Correct answer: option 4
$f(x)=\left\{\begin{array}{l}x^2 ; x \geq 0 \\ x ; x<0\end{array}\right.$
$f(f(x))=\left\{\begin{array}{l}(x^2)^2 ; x \geq 0 \\ x ; x<0\end{array}\right.$