古诗赏析 。
                                                                                                                                               伤桃源薛道士
                                                                                                                                                     刘禹锡
                                                                                                                             坛边松在鹤巢空，白鹿闲行旧径中。
                                                                                                                              手植红桃千树发，满山无主任春风。

图中的玻璃罐模拟池塘生态系统．请回答（1）﹣（4）题．

一元二次方程x²﹣6x+1=0的根为____ 

在△ABC中，若$\sin A=\frac{1}{2}$，tanB=1，则这个三角形是（   ）