摘要： 已知函数$\textit{f}(\textit{x})=\textit{a}\ln\textit{x}+\textit{x}$, $\textit{x}\in(0$,$+\infty)\text{且}\textit{a}\in\textbf{R}$. $(1)$讨论函数$\textit{f}(\te 阅读全文