# If $f:R\rightarrow R$ is defined $f(x)=x^2-3$ then $f^{-1}x$ = ?

$\begin{array}{1 1} \sqrt {x+3} \\ \sqrt {x} +3 \\ x+ \sqrt 3 \\ none\;of\;these \end{array}$

$y=f(x)=x^2-3$
$\Rightarrow x=\sqrt{y+3}=f^{-1}(y)$
$\Rightarrow f^{-1}(x)=\sqrt{x+3}$
answered May 13, 2013