在初三期末复习中,一道填空题的探究出现了几次惊人的雷同错解,回顾艰难的探“险”过程,一波三折,扣人心弦,余音绕梁,现整理成文,以飨读者.1.浅尝辄止,误入歧途.题目如图1,将直角三角板ABC绕直角顶点B顺时针旋转90°后得到△DBF.若∠A=30°,BC=1,则斜边AC扫过的面积S为____、 During the review at the end of the third period, a striking resemblance to the problem of blank-filling was revealed. After reviewing the difficult process of exploration and adventure, twists and turns, exciting and overwhelming, is now organized and written to readers. , Go astray.The subject is shown in Figure 1, the right angle triangle ABC around the right angle vertex B clockwise rotation of 90 ° get △ DBF.If ∠A = 30 °, BC = 1, then bevel AC swept the area S is _ ___,