1 I don`t know if they ___ A party next sunday A will have B would have C had D can have 为什么是B 2 2009•兰州)如图,某公路隧道横截面为抛物线,其最大高度为6米,底部宽度OM为12米.现以O点为原点,OM所在直
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![1 I don`t know if they ___ A party next sunday A will have B would have C had D can have 为什么是B 2 2009•兰州)如图,某公路隧道横截面为抛物线,其最大高度为6米,底部宽度OM为12米.现以O点为原点,OM所在直](/uploads/image/z/8853630-6-0.jpg?t=1+I+don%60t+know+if+they+___+A+party+next+sunday+A+will+have+B+would+have+C+had+D+can+have+%E4%B8%BA%E4%BB%80%E4%B9%88%E6%98%AFB+2+2009%26%238226%3B%E5%85%B0%E5%B7%9E%EF%BC%89%E5%A6%82%E5%9B%BE%2C%E6%9F%90%E5%85%AC%E8%B7%AF%E9%9A%A7%E9%81%93%E6%A8%AA%E6%88%AA%E9%9D%A2%E4%B8%BA%E6%8A%9B%E7%89%A9%E7%BA%BF%2C%E5%85%B6%E6%9C%80%E5%A4%A7%E9%AB%98%E5%BA%A6%E4%B8%BA6%E7%B1%B3%2C%E5%BA%95%E9%83%A8%E5%AE%BD%E5%BA%A6OM%E4%B8%BA12%E7%B1%B3%EF%BC%8E%E7%8E%B0%E4%BB%A5O%E7%82%B9%E4%B8%BA%E5%8E%9F%E7%82%B9%2COM%E6%89%80%E5%9C%A8%E7%9B%B4)
1 I don`t know if they ___ A party next sunday A will have B would have C had D can have 为什么是B 2 2009•兰州)如图,某公路隧道横截面为抛物线,其最大高度为6米,底部宽度OM为12米.现以O点为原点,OM所在直
1 I don`t know if they ___ A party next sunday A will have B would have C had D can have 为什么是B 2 2009•兰州)如图,某公路隧道横截面为抛物线,其最大高度为6米,底部宽度OM为12米.现以O点为原点,OM所在直线为x轴建立直角坐标系.
(1)直接写出点M及抛物线顶点P的坐标;
(2)求这条抛物线的解析式;
(3)若要搭建一个矩形“支撑架”AD-DC-CB,使C、D点在抛物线上,A、B点在地面OM上,则这个“支撑架”总长的最大值是多少?为什么oa =bm!谢谢了30分 虽然不多
1 I don`t know if they ___ A party next sunday A will have B would have C had D can have 为什么是B 2 2009•兰州)如图,某公路隧道横截面为抛物线,其最大高度为6米,底部宽度OM为12米.现以O点为原点,OM所在直
数学题:
(1)因为宽为12米,高度为6米,且以o为原点,则点M坐标为(12,0),顶点P(6,6)
(2)设方程y=ax*x+bx+c
已知抛物线经过的三个点(0,0),(12,0),(6,6)
则解出 a=-1/6,b=2,c=0;
则方程为y=-1/6x*x+2x
(3)设A坐标(a,0),B坐标(b,0)
则可知D(a,-1/6a*a+2a) C(b,-1/6b*b+2b)
所以周长L=2(b-a)+2(-1/6a*a+2a)
又因为D,C的纵坐标相等,即C,D是关于x=6对称的
所以有a=6-x,b=6+x;
带入L则L=-1/3x*x+2x+12=-1/3(x-3)(x-3)+15
即x=3时有最大值,也就是QA=BM=3
其实OA=BM是肯定的,因为这是个矩形
英语真的解释不来
我作为一个老师 对天发誓 第一个英语题不可能是B 题出错了
应该选A就是一个宾语从句
数学题(2)设抛物线方程为y=a(x-x0)^2+b ,再把M点和P点的坐标带进去就能求出来的
英语B 这应该是间接引语吧 I don't know“Will they have a party next Sunday”我也不知道知道对不
用if引导的间接引句用一般现在时态 ,选B;
数学题 1 ,M(12,0) P(6,6)
2, (X-6)(X-6)=—2y+6