Question: Determine if the function \[h(x)=\left\{ \begin{aligned} & \text{-}{{x}^{\text{2}}}\text{, if }x\text{ }\le \text{ 0} \\ & \sqrt{x},\text{ if }x\text{ }>\text{ 0} \\ \end{aligned} \right.\] is one-to-one. Explain your answer.