浙江省东阳中?019届高三下学期开学考试数学试题(解析? - 百度文库

b2+2c2

=36٣ SABD=?c?

=?c? ٴɵãSABD=?c?=c

3d=c d=c

=2ҽc2

=8ʱȡȺţ

ѡB

ƽıηεʽԼƽıεʿɵb2

+2c2

=36ɵõd=c

ûʽֵ

⿼ڼеӦãѧתͼ 10.𰸡A

⣺abca+b+c=0a0c0b=-a-cࣼ0 ɸϵĹϵ֪x1+x2=

=

=2+x1x2==

=1+

ࣨx1-x22

=x1+x22

-4x1x2=2+2

-41+=2

-=-22

-4

x1+x2=02+0-20 x1x2=

01+

0-

-2-

ࣨ-22

-4ʣ12

|x1-x2|ʣ2

ѡA

ݸϵĹϵóķΧñʾ|x1-x2|2

Ӷ|x1-x2|ȡֵΧ ⿼һԪη̸ϵĹϵκʣе⣮ 11.𰸡4 2

⣺⣬˫ߵķΪx2

-

=1

a=1b=

c=

=2

˫ߵĽ2c=22=4

e==2 ʴΪ42

⣬˫ߵı׼̿ɵa=1b=˫ߵļʼɵc=2˫ߵĽ๫

ʽԼʹʽɵô𰸣

⿼˫ߵı׼̣ע˫ߵĽ2c

12.𰸡

7

⣺ڡABCУABCԵı߷ֱΪabc֪

Ҷɵã

ã ࣬ab=6

ߣcosC=

࣬a=1b=6a=6b=1

a+b=7 ʴΪ

7 ҶɵãӶõɣab=6ɴ

Ҷa+b

⿼εĽǼ߳󷨣漰ҶҶȻ֪ʶ֤黯ת˼롢뷽˼룬е⣮ 13.𰸡2n+1

⣺Ȳ{an}ĹΪda2=5a1+a4=12 ɵãã an=3+n-12=2n+1

=

=[-]

{bn}ǰnSn=[1-++

++

]=

= ʴΪ 2n+1

õȲеͨʽ͹ȣɵõȲ{an}ͨʽ{bn}ͨʽ

ͣ

ҪȲеͨʽͣе⣮

14.𰸡1 [-

]

⣺⣬f-x=lne-2x

+1+mx=lne2x

+1-mx

2mx=lne2x

+1-lne-2x

+1=2x

m=1

a2+ab+4b2

m

4|ab|+ab1 -abܣ

ʴΪ1[-]

żĶ壬mûʽabȡֵΧ

⿼żĶ壬ʽãе⣮ 15.𰸡222

⣺ø巨24ѧγɵ23β2壬ֳ飬C232

=253֣ͬģ8881֣2ͬģ112222203318441655

146612771099610104

1111210

3=30 ÿУһͬշ253-1-30=222

ʴΪ222

ø巨24ѧγɵ23β2壬ֳ飬ųͬģ2ͬģԽ

1Ҫԭй֪ʶ㣬ķǣԪλȵԭ򣬲շ󷨵ȷڽʱʱҲ򷴵Ľ˼뷽ڼʱȡųļɣоĶΪӣȡоٷǽϸõһַ 16.𰸡

⣺ֱy=y=ͼ

ֱȡ㣨x

xΪͼϸȡһľƽ

PΪy=xy=

Ľ㣬

PO2=x2+

2

=18PO=

ҽx=3ʱȡȺţ

ʵõСֵΪOP-2=

ʴΪ ֱy=

y=

ͼ󣬷ֱȡ㣨x

xΪͼϸȡһľ룬ν

ϵ˼룬ûʽʼ⣮

Ҫνϵ˼룬ͼ֮ľ빫ʽԼʽʣ

е⣮

17.𰸡0

⣺⣬ͼ

ԲC1ϲڵPʹɵPԲC2߻ഹֱ

ɡAPO45㣬

sinAPOsin45㣬

e==

=

ԲC1ʵȡֵΧǣ

ʴΪ

ͼԲC1ϲڵPʹɵPԲC2߻ഹֱɵáAPO45㣬óۣ

⿼Բı׼̼ʡֱԲеʣе⣮18.𰸡⣺

=

=

T=

ɵ

ȡk=0

ȡk=1

֡x[0]

fxĵΪ

öǣĹʽԼǻ򼴿fxСڣ fxĵ[0]󽻼ɵõ䣮

ҪǺͼʣǺʽлǽĹؼ 19.𰸡⣺1an+1=

an+

4

n+1

an+1=4nan+2

bn+1=bn+2bn+1-bn=2

{bn}Ϊ1Ϊ2ĵȲУ 2Ϊ{bn}Ϊ1Ϊ2ĵȲУ bn=1+2n-1=2n-1

Ϊbn=4n

an

an=

S

n=

+ + ++ +

Sn= + + ++

+

S

n= +2 + + ++ - =

+2 -

Sn=

- -

ΪSn+nan

*

nN

-

-

nN*

ˡ

+

nN*

Ϊn12n-11

ҽn=1ʱȡȺţ Ϊ

ҽn=1ʱȡȺţ

+ ҽn=1ʱȡȺ Ԧˡ

Ԧ˵СֵΪ

1֪4

n+1

an+1=4nan+2bn+1=bn+2{bn}Ϊ1Ϊ2ĵȲУ

2֪bn=1+2n-1=2n-1bn=4n

an֪an=

ɴλSn=-

-

ȻSn+nanݶnN*

ʵ˵Сֵ

⿼еʺӦãʱҪעλã⣬ϸ 20.𰸡֤ADƽABCADDG

BFADBFDG

DE=DFGEFе㣬EFDG BFEF=FDGƽBCEF

򣩽⣺ȡBCеHHGȡHGеOOPOE PODGPOƽBCEF OEPPEƽBCEFɵĽǣ

AD=EF=3DE=DF=2

֪ɵADDGһõBFDGDE=DFGEFе㣬ɵEFDGȻ洹ֱжɵDGƽBCEF

ȡBCеHHGȡHGеOOPOE֤OEPPEƽBCEFɵĽǣȻֱοɵPEƽBCEF ɽǵֵ

⿼ֱƽ洹ֱжռ˼άǵ󷨣е⣮ 21.𰸡⣺1ֱABķΪy=kx+3k0Ax1y1Bx2y2

yɵx2-2pkx-6p=0

x1+x2=2pkx1x2=-6p

|AB|= ?

=2 ?

߹Plֱֱ߽ڵCDʽkΪ-

|CD|=2

?

2 ? =2

?

=8 k2

=1p=2 Cx2

=4y

2MΪABе㣬NΪCDе㣬 ɣ1ɵx

M= x1+x2=pkyM=pk2

+3

Mpkpk2

+3

P03

|PM|= =pk kΪ-

|PN|=

?

PMNS=

2

= p2k+

|PM|?|PN|= p? ?

p2

ҽk=1ʱȡȺ ʡPMNSСֵp2

1ֱABķΪy=kx+3k0Ax1y1Bx2y2yɵ

x2-2pkx-6p=0ҳʽ|AB|ʽkΪ-|CD|ٸ

2ϣ1M꣬ݵľ빫ʽ|PM|kΪ-|PNʾεûʽ

⿼ֱߺߵλùϵΤﶨҳʽεʽʽ֪ʶת뻯е⣮ 22.𰸡⣺IΪ-1+ޣ

f'x0?-1x2a-1f'x0?x2a-1 fxĵΪ-12a-1 fxĵݼΪ2a-1+ޣ fxļֵΪ2aln2a-2a+1

II֤Ҫ֤

֤

֤

֤

ɣI֪fxڣ0+ޣϵݼ fxf0=0 ln1+xx

ۼӵã

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