088]解:(1)法一:由图象可知:抛物线经过原点. 设抛物线解析式为. 把.代入上式得:···················································································· 1分 解得······················································································· 3分 ∴所求抛物线解析式为········································································ 4分 法二:∵.. ∴抛物线的对称轴是直线. 设抛物线解析式为()······························································ 1分 把.代入得 解得··········································································· 3分 ∴所求抛物线解析式为.····························································· 4分 (2)分三种情况: ①当.重叠部分的面积是.过点作轴于点. ∵.在中... 在中... ∴. ∴.··············································· 6分 ②当.设交于点.作轴于点. .则四边形是等腰梯形. 重叠部分的面积是. ∴. ∴.··········· 8分 ③当.设与交于点.交于点.重叠部分的面积是. 因为和都是等腰直角三角形.所以重叠部分的面积是. ∵.. ∴. ∴. ∴ .················································ 10分 (3)存在 ···································································································· 12分 ··································································································· 14分 【查看更多】

 

题目列表(包括答案和解析)

9、如图是抛物线y=ax2+bx+c的一部分,其对称轴为直线x=1,若其与x轴一交点为B(3,0),则由图象可知,不等式ax2+bx+c>0的解集是
x<-1或x>3
.

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如图,是二次函数y=ax2+bx+c图象的一部分,其对称轴为直线x=1,若其与x轴一交点为A(3,0),则由图象可知,方程ax2+bx+c=0的另一个解是(  )

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12、如图,是二次函数y=ax2+bx+c图象的一部分,其对称轴为直线x=1,若其与x轴一交点为A(3,0),则由图象可知,不等式ax2+bx+c<0的解集是
-1<x<3
.

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如图是抛物线y=ax2+bx+c的一部分,其对称轴为直线x=2,若其与x轴一交点为B(5,0),则由图象可知,不等式ax2+bx+c>0的解集是
x>5或x<-1
x>5或x<-1
.

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2、“已知二次函数y=ax2+bx+c的图象如图所示,试判断a+b+c与0的大小.”一同学是这样回答的:“由图象可知:当x=1时y<0,所以a+b+c<0.”他这种说明问题的方式体现的数学思想方法叫做(  )

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