论文部分内容阅读
2012年安徽省中考数学试卷第23题:如图1,排球运动员站在点O处练习发球,将球从O点正上方2m的A处发出,把球看成点,其运行的高度y(m)与运行的水平距离x(m)满足关系式y=a(x-6)~2+h.已知球网与O点的水平距离为9m,高度为2.43m,球场的边界距O点的水平距离为18m.(1)当h=2.6时,求y与x的关系式(不要求写出自变量x的取值范围);(2)当h=2.6时,球能否越过球网?球会不会出界?请说明理由;(3)若球一定能越过球网,又不出边界,求h的取
As shown in Figure 1, a volleyball player stands at Point O and practices the serve. The ball is sent out from point A at a distance of 2m just above point O, and the ball is regarded as a point. The height of the running y ( (x-6) ~ 2 + h. It is known that the horizontal distance between the net and the O-point is 9m and the height is 2.43m. The distance between the stadium and the O The horizontal distance of the point is 18m. (1) When h = 2.6, find the relation between y and x (do not need to write the range of the argument x); (2) When h = 2.6, Ball net? The ball will not go out of bounds? Please explain the reasons; (3) If the ball will be able to cross the net, but also out of bounds, h h