优课网
首页
数学
语文
英语
化学
物理
政治
历史
生物
首页
> 已知关于x的方程x2-2(k+1)x+k2+2k-1=0①(1)试判断方程①的根的情况;(2)如果a是关于y的方程y2-(x1+x2-2k)y+(x1-k)(x2-k)=0②的根,其中x1,x2为方程
已知关于x的方程x2-2(k+1)x+k2+2k-1=0①(1)试判断方程①的根的情况;(2)如果a是关于y的方程y2-(x1+x2-2k)y+(x1-k)(x2-k)=0②的根,其中x1,x2为方程
题目简介
已知关于x的方程x2-2(k+1)x+k2+2k-1=0①(1)试判断方程①的根的情况;(2)如果a是关于y的方程y2-(x1+x2-2k)y+(x1-k)(x2-k)=0②的根,其中x1,x2为方程
题目详情
已知关于x的方程x
2
-2(k+1)x+k
2
+2k-1=0 ①
(1)试判断方程①的根的情况;
(2)如果a是关于y的方程y
2
-(x
1
+x
2
-2k)y+(x
1
-k)(x
2
-k)=0②的根,其中x
1
,x
2
为方程①的两个实数根,求代数式
(
1
a
-
a
a+1
)÷
4
a+1
×
a
2
-1
a
的值.
题型:解答题
难度:中档
来源:不详
答案
(1)∵a=1,b=-2(k+1),k=k2+2k-1,
∴△=b2-七ak=[-2(k+1)]2-七(k2+2k-1)=8>0,
∴方程有两个不相等的实数根;
(2)∵方程①中x1+x2=2(k+1),x1x2=k2+2k-1
代入方程②中,可得到:y2-2y-1=0,
因a是方程②的根,则a2-2a-1=0,
∴a2-1=2a,把a2-1=2a整体代入所求代数式,
∴
(
class="stub"1
a
-
class="stub"a
a+1
)÷
class="stub"七
a+1
×
a
2
-1
a
=
-2
a
2
七
a
2
=-
class="stub"1
2
∴所求代数式的值为-
class="stub"1
2
.
上一篇 :
He hurried to the station,onl
下一篇 :
(1)请从三个代数式4x2-y2,2xy+y2,4
搜索答案
更多内容推荐
Here are some of the suggestions you need __________your hair.A.taking care of B.to be taken of C.to
It was________that many people were injured in the accident.A.reportedB.to be reportedC.reportingD.r
The traffic rule says young children under the age of four and ________ less than 40 pounds must be
Nobody but doctors or nurses and those ________ by Dr Li ________ to enter the patient’s room.A.bein
a college or university in the USA, Chinese and other international students must show and prove the
If you’d like me to do the job for you, I want to ____________ in cash.A.get paidB.paidC.be payingD.
Some students didn’t get a brief summary ________ in their essays.A.includeB.includedC.includingD.in
化简求值:(1)已知|a-1|=2,求a2-4a+4-4a2-4a+1的值;(2)先化简,再求值:x+1x2+x-2÷(x-2+3x+2),其中x=3+2.-数学
某厂一个车间计划在一定时间内加工560个零件,在加工120个零件后,改进了操作技术,每天能多加工15个零件,结果比原计划提前3天完成任务。则改进操作技术后每天加工的零件个-八年级数学
There is no doubt that our educational system leaves something __________. A.being desiredB.to be de
The direct flight has proved successful,________ Taiwan another tourist destination for people on th
如果2a-b=0,那么a2-b2a2-2ab+b2的值是______.-数学
When ________ about his school life, Tim thought it colorful.A.askedB.askingC.to askD.asks-高三英语
Johnny wanted to ride his new bicycle in the street, but his mother told him ________.A.not toB.not
He is said ________ college in America, studying music.A.to be attendingB.that attendC.to be attend
In 2012 Mo Yan won the Nobel Prize for Literature, ________ a host of imitators.A.inspiringB.inspir
He is afraid to face the difficulty he thinks he'll have ________ the driving test tomorrow; h
The Diaoyu islands have been part of China's territory since ancient times, ________ as importa
In order to jump, your body changes the chemical energy ________ in the food you have eaten into me
When ______ help, one always says “Thank you” or “It’s very kind of you”A.offeringB.offeredC.to offe
先化简,后求值:x+1x+2÷x2-1x-1,其中x=3-2.-数学
化简后求值:已知a=2-2,b=2+2,求a3b+a2b2a2+2ab+b2÷a2-aba2-b2的值.-数学
________to get a seat for the concert,he didn’t mind standing in a queue all night.A.DetermineB.To b
武汉市某校组织甲、乙两班学生参加“美化校园”的义务劳动,若甲班做2小时,乙班做3小时则恰好完成全部工作的一半;若甲班先做2小时后另有任务,剩下工作由乙班单独完成,则乙-八年级数学
This project requires close teamwork. _______Will be achieved unless we work well together.A.Nothing
若4x-3y=0(y≠0),则(x+y):y=______.-数学
Unless ________ to answer questions, the pupils won't talk in Mrs Smith's class.A.askingB
________ from the bright smile on his face, he ________ in passing the job interview.A.Judging; mus
先化简,再求值:x2-4x2+4x+4÷(x-2-2x-4x+2),其中x=3.-数学
1m+1n=1m+n,则nm+mn的值为多少?-数学
Either you or one of your students ________ to attend the meeting ________ tomorrow.A.are; to be hel
With all the books he was interested in ________, he left the library and went back to his dorm.A.b
. — Why was Professor Johnson unhappy those days? — The only reason was ________the theory he stick
With the couple________in a nearby town,the house seems pretty empty most of the time.A.workB.to wor
小明家准备装修一套新住房,若甲、乙两个装饰公司,合做需6周完成,需工钱5.2万元;若甲公司单独做4周后,剩下的由乙公司来做,还需9周才能完成,需工钱4.8万元,若只选一-八年级数学
先将x2+3xx-1-(1x-1)化简,然后请自选你喜欢的一个适合的x值代入,再求原式的值.-数学
As a considerate secretary, she never fails to know what ________ in her daily routine.A.to expect
________ the earth to be flat, many feared that Columbus would fall off the edge of the earth.A.Hav
计算:(a+b-b2b-a)÷(a-a2a-b).-数学
已知x-3y=0,求(2x+y)(x-y)x2-2xy+y2的值.-数学
已知a+b=3,ab=1,则ab+ba的值等于______.-数学
下列运算正确的是()A.ca-c+1a=-1a\;B.12a+12b=12(a+b)C.ba+bc=2ba+cD.x2+y2z÷zx2+y2=x2+y2z2-数学
______more effectively with foreign firms, many Chinese firms have turned to new technology.A.Being
I stopped the car________a short break as I was feeling tired. (2013·山东,29)A.takeB.takingC.to take D
They suggested that the professor ________ just now ________ chairman of the meeting.A.referring to
The old man sat in front of the radio every evening, ______ his favorite program.A.dying to hearB.wa
某校初三(2)班的师生到距离10千米的山区植树,出发1个半小时后,张锦同学骑自行车从学校按原路追赶队伍,结果他们同时到达植树地点,如果张锦同学骑车的速度比队伍步行的速度-八年级数学
若x2+2x-2=0,求代数式(x2x-1-2x1-x)÷2x-1-2的值.-数学
—Can you introduce me a high quality machine?—My pleasure. ________ well even on wet roads, this kin
No matter how frequently ________, the works of Beethoven still attract people all over the world.A
返回顶部
题目简介
已知关于x的方程x2-2(k+1)x+k2+2k-1=0①(1)试判断方程①的根的情况;(2)如果a是关于y的方程y2-(x1+x2-2k)y+(x1-k)(x2-k)=0②的根,其中x1,x2为方程
题目详情
(1)试判断方程①的根的情况;
(2)如果a是关于y的方程y2-(x1+x2-2k)y+(x1-k)(x2-k)=0②的根,其中x1,x2为方程①的两个实数根,求代数式(
答案
∴△=b2-七ak=[-2(k+1)]2-七(k2+2k-1)=8>0,
∴方程有两个不相等的实数根;
(2)∵方程①中x1+x2=2(k+1),x1x2=k2+2k-1
代入方程②中,可得到:y2-2y-1=0,
因a是方程②的根,则a2-2a-1=0,
∴a2-1=2a,把a2-1=2a整体代入所求代数式,
∴(
∴所求代数式的值为-