A:to his students to arrive
B:to his students for arriving
C:at his students to arrive
D:at his students for arriving
下列情况中运动状态没有发生改变的是( )
在每个小正方形的边长为1的网格中.点A,B,D均在格点上,点E、F分别为线段BC、DB上的动点,且BE=DF.
(Ⅰ)如图①,当BE=52时,计算AE+AF的值等于 ____
(Ⅱ)当AE+AF取得最小值时,请在如图②所示的网格中,用无刻度的直尺,画出线段AE,AF,并简要说明点E和点F的位置如何找到的(不要求证明)____
若实数a,b,c满足a+b+c=0,且a<b<c,则函数y=cx+a的图象可能是( )