设函数f(x)=ax2+2x+blnx在x=1和x=2时取得极值.(ln2≈0.

题型:解答题

问题:

设函数f(x)=ax2+2x+blnx在x=1和x=2时取得极值.(ln2≈0.7)
(1)求a、b的值;
(2)求函数f(x)在[
1
2
,2]
上的最大值和最小值.
考点:函数的单调性与导数的关系函数的最值与导数的关系
题型:解答题

工资支付应遵循的一般规则有哪些

题型:解答题
选择下列单词填空,将中英文词组搭配起来,并将序号写在题前括号里。
( ) 1. fly                          
( ) 2.              a snowman 
(     ) 3. plant                  
(     ) 4.              mountains 
(     ) 5.              a picnic  
A. 堆雪人   
B. 放风筝 
C. 野炊     
D. 植树                                                                           
E. 爬山  
climb        trees         kites        have         make
题型:解答题

投资者在进行债券投资时,需考虑的风险有()。

A.价格风险

B.违约风险

C.债券赎回风险

D.通货膨胀风险

E.提前偿付风险

题型:解答题
As a kid, I spent my summers with my grandparents in Texas. And every few summers, we’d __16__ the caravan (旅游团队), a group of Airstream trailer owners who __17__ together around the U.S. and Canada.
I loved and worshipped my grandparents and I really looked __18__ to these travels. On one particular __ 19__ ,I was about 10 years old. I was rolling around in the backseat. My grandfather was __20__ . And my grandmother had the passenger seat. She smoked throughout these trips, and I hated the __21__.
At that age, I’d take any excuse to make estimates(估计) and do minor __22__.At any rate, I decided to do the math for my __23__. I estimated the number of  cigarettes per days, estimated the number of __24__ per cigarette and so on. When I was satisfied that I’d come up with a reasonable number, I poked my head  into the __25__ of the car, tapped my grandmother __26__ the shoulder, and proudly proclaimed, “At two minutes per puff, you've taken nine years off your __27__!” Because the ad said, every puff of a cigarette takes some  number of minutes __28__ smoker’s life.
I expected to be applauded for my __29__ and arithmetic skills. That’s not what happened.__30__, my grandmother burst into __31__. I sat in the backseat and did not know what to do. My grandfather was a highly intelligent, __32__ man. He had never said a harsh word to me. He pulled __33__ onto the shoulder of the highway. He stopped and got out of the car, __34__ me, and after a bit of silence,he gently and __35__ said, “Jeff, one day you’ll understand that it’s harder to be kind than clever.”  
小题1:
A.takeB.join C.attend D.visit
小题2:
A.workB.studyC.travelD.explore
小题3:
A.forwardB.backwardC.towardD.upward
小题4:
A.holidayB.researchC.trip D.return
小题5:
A.talkingB.readingC.trainingD.driving
小题6:
A.sceneB.smellC.band D.type
小题7:
A.arithmetic(算数)B.questionC.gameD.problem
小题8:
A.grandfatherB.grandmotherC.visitorD.car
小题9:
A.casesB.smokesC.kindsD.puffs(烟头)
小题10:
A.windowB.seatC.backD.front
小题11:
A.atB.inC.onD.under
小题12:
A.tourB.lifeC.distanceD.date
小题13:
A.awayB.fromC.withD.off
小题14:
A.clevernessB.coolnessC.happinessD.ability
小题15:
A.EventuallyB.InsteadC.UnfortunatelyD.Though
小题16:
A.wordsB.laughtersC.tearsD.screams
小题17:
A.stubbornB.determinedC.lonelyD.quiet
小题18:
A.over B.in C.awayD.up
小题19:
A.noticedB.lookedC.glaredD.glanced
小题20:
A.angrilyB.excitedlyC.calmlyD.coldly
题型:解答题

下列关于植物组织培养和胚胎工程技术的叙述.错误的是()

A.胡萝卜根韧皮部细胞经组织培养发育成新植株体现了体细胞全能性

B.早期胚胎培养与动物细胞培养的培养液通常都需加入血清

C.一次给受体母羊植入多个胚胎,可增加双胞胎和多胞胎的比例

D.可用植物的叶肉细胞作外植体通过组织培养大量繁殖无病毒的植株

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