Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Relations and Functions

Question:

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

Options:

$x^2 ; x ; x \geq 0$

$x^4, x \geq 0 ; -x^2 ; x<0$

$x^4, x \geq 0 ; x^2<0$

$x^4, x \geq 0 ; x, x<0$

Correct Answer:

$x^4, x \geq 0 ; x, x<0$

Explanation:

$f(x)=\left\{\begin{array}{l}x^2 ; x \geq 0 \\ x ; x<0\end{array}\right.$

$f(f(x))=\left\{\begin{array}{l}(x^2)^2 ; x \geq 0 \\ x ; x<0\end{array}\right.$