کدام تابع، یکبهیک است؟
1 )
$f(x)=\left\{ \begin{matrix}
x+1\,\,\,\,:x\ge 0 \\
{{x}^{2}}+1\,\,\,:x \lt 0 \\
\end{matrix} \right.$
2 )
$g(x)=\left\{ \begin{matrix}
x-1\,\,\,\,:x\ge 0 \\
{{x}^{2}}+1\,\,\,:x \lt 0 \\
\end{matrix} \right.$
3 )
$h(x)=\left\{ \begin{matrix}
-x+2\,\,\,\,\,\,:\,x\ge 0 \\
{{x}^{2}}+1\,\,\,\,\,\,\,:x \lt 0 \\
\end{matrix} \right.$
$k(x)=\left\{ \begin{matrix}
-x\,\,\,\,\,\,\,\,\,:\,x\ge 0 \\
{{x}^{2}}+1\,\,\,\,\,\,\,:x \lt 0 \\
\end{matrix} \right.$