乙题: 解:(1)因为反比例函数的图象经过点 有.················································································································ 2分 .····················································································································· 3分 所以反比例函数的解析式为.············································································· 4分 (2)当为一.三象限角平分线与反比例函数图像的交点时. 线段最短.············································································································ 5分 将代入.解得.即..····················· 6分 .··········································································································· 7分 则.··········································································································· 8分 又为反比例函数图像上的任意两点. 由图象特点知.线段无最大值.即.·················································· 9分 查看更多

 

题目列表(包括答案和解析)

(2012•峨边县模拟)甲题:关于x的一元二次方程x2+(2m+1)x+m2=0的实数解为x1和x2
(1)求m的取值范围.
(2)当
x
2
1
-
x
2
2
=0时,求m的值.
乙题:如图,在△ABC中,AC=AB,以AB为直径的半⊙O交AC于点E交BC于点D,连AD、BE.
(1)求证:△BEC∽△ADC;
(2)BC2=2AB•CE.

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小明学习了“第八章  幂的运算”后做这样一道题:若(2x-3)x+3=1,求x的值,他解出来的结果为x=1,老师说小明考虑问题不全面,聪明的你能帮助小明解决这个问题吗?
小明解答过程如下:
解:因为1的任何次幂为1,所以2x-3=1,x=2.且2+3=5
故(2x-3)x+3=(2×2-3)2+3=15=1,所以x=2
你的解答是:
解:①∵1的任何次幂为1,所以2x-3=1,x=2.且2+3=5,
∴(2x-3)x+3=(2×2-3)2+3=15=1,
∴x=2;
②∵-1的任何偶次幂也都是1,
∴2x-3=-1,且x+3为偶数,
∴x=1,
当x=1时,x+3=4是偶数,
∴x=1;
③∵任何不是0的数的0次幂也是1,
∴x+3=0,2x-3≠0,
解的:x=-3,
综上:x=2或3或1.
解:①∵1的任何次幂为1,所以2x-3=1,x=2.且2+3=5,
∴(2x-3)x+3=(2×2-3)2+3=15=1,
∴x=2;
②∵-1的任何偶次幂也都是1,
∴2x-3=-1,且x+3为偶数,
∴x=1,
当x=1时,x+3=4是偶数,
∴x=1;
③∵任何不是0的数的0次幂也是1,
∴x+3=0,2x-3≠0,
解的:x=-3,
综上:x=2或3或1.

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甲、乙两人解方程组
ax+by=2
cx-7y=8
,甲正确地解得
x=3
y=-2
,乙因为把c看错,误认为d,解得
x=-2
y=2
,求a、b、c、d.

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计划修建铁路1200km,那么铺轨天数y(天)是每日铺轨量x的反比例函数吗?解:因为
 
,所以y是x的反比例函数.

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甲题:已知x1、x2是关于x的一元二次方程x2-2x+a-1=0的两个实数根
(1)若x1+2x2=3-
2
,求x1、x2及a的值;
(2)若s=ax1x2+3x1+3x2-3a,求s的取值范围.
乙题:如图,在Rt△ABC中,∠C=90°,AC:AB=
3
:2

(1)求BC:AC的值;
(2)延长CB到点D,使DB:DC=2:3,连接AD.
①求∠D的度数;②若AD=12,求△ABC三边的长.
解:我选做
题.

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