论文部分内容阅读
教学生解数学题,要将解题方法落在学生的最近知识生长点上,自然地引导学生想,鱼渔兼授,让学生在思维的自然生成中获得问题的解决!1试题呈现(由2017年盐城市中考数学第27题改编)如图1,在平面直角坐标系中,抛物线y=-1/2x~2-3/2x+2与x轴交于A,B两点(点A在点B的左边),与y轴交于C点,点D为直线AC上方抛物线上一动点,过点D作DF丄AC,垂足为F,联结CD。是否存在点D,使得△CDF中的某个角恰好等于∠OAC的2倍?若存
Teaching students solve math problems, the problem-solving methods should fall on the students’ recent knowledge growth point, and naturally guide students to think, fish and fisheries, so that students in the natural generation of thinking to get the problem solved! 2017 Yancheng senior high school entrance examination mathematics twenty-seventh questions adapted) Figure 1, in a rectangular plane coordinate system, the parabola y = -1 / 2x ~ 2-3 / 2x + 2 and the x-axis at A, B two points At the left side of point B), intersects the y-axis at point C, point D is the moving point above the parabola on the straight line AC, point D is DF 丄 AC, and foot-drop F is the connecting CD. Is there a point D such that an angle in ΔCDF exactly equals 2 times ∠OAC?