數(shù)列求和練習(xí)(奇偶項(xiàng))

nn19919899nn12100n243nn32+2nnn*nnn2*n1*nnn*nn25nnnnn19919899nn12100n243nn32+2nnn*nnn2*n1*nnn*nn25nnnnnnnnnn413nnnn數(shù)列綜合奇偶項(xiàng)）一選題共1小題）{}qnaa0

＜q11aaT1n199A

B

C

D二填題共1小題）

當(dāng)為數(shù)時(shí)當(dāng)偶數(shù)時(shí)

f+f+1+a+a++三解題共小題{}a3aa1{}221N*

}nTT{}nkN

9k{}{}n+1{}a2nN

2{}TTmNmS{}{}n2nN{}{}

，，

{n

}n{}nS1{}2{}

b1

3

n

{}a1{

，}

N*第頁(yè)（共頁(yè)）nnnnnnnnnnk11231nkkn12k+1k35nn1n2*n2*2nnnnn1n12nnnnnnnnnnk11231nkkn12k+1k35nn1n2*n2*2nnnnn1n12nn25nnn30n2n+1nnn1nnn+1nn2nnnnn22{}{}n

{}{n+2}{}0{}kk++{}+1aak13﹣a{}為偶數(shù){}a

n

為奇數(shù)

1

nNa

﹣

1

Na{}{}T{}na0a1{}2++{}430{}{}30T{}3a﹣{}{}

，求

n

{}2+331{}2{}2T{}n

{n

}

{}{}{}2T第頁(yè)（共頁(yè)）nn1424nnnnnnn1125nnn2n35nn1424nnnnnnn1125nnn2n35nnnnn2nnnnnnnnn1n10{}nI{}{}為奇數(shù)

2a12SII

c

為偶數(shù)

T{}n{}Sa1{}

S102b

，為數(shù){}2n+1，為數(shù){}a{}{}2S{}a1N*{}

nN*{}1

2{}10第頁(yè)（共頁(yè)）21979829910011119899100198+19799…99100299100nnn+1123100134992n2421979829910011119899100198+19799…99100299100nnn+1123100134992n24n1n1﹣n+1n3n+23n*n11n1參考答案與試題解析一選題共1小題）aa1aq1a1

＜a110q1TaaaD二填題共1小題）

qaa11

an+f+1

是奇數(shù)是偶數(shù)a

+a2a++a+aa++a+a++a2+2+2++2100三解題共小題{}q0a23q29qq{}3a

13nN*22n1nlog321

n

1

1

12kNkanaa272

n

5n︸

3a+13

第頁(yè)（共頁(yè)）n532n11n1n1nnnnnnn1nnnnn13111nn+1n13n1nn532n11n1n1nnnnnnn1nnnnn13111nn+1n13n1n

＜

{}a

2a+nn1

T11

T2b﹣﹣b1bbb2{}2﹣﹣2B

}dnS32a32a+78d52a12n2bb+bbb﹣+2n+1n2n+4nT1

，

{

}1

21

1

第頁(yè)（共頁(yè)）1n+1nnnn1n12n1k21111n1﹣1n1n1﹣nn1﹣12nn1223435435IIa+11n+1nnnn1n12n1k21111n1﹣1n1n1﹣nn1﹣12nn1223435435IIa+13+12ak﹣32k+1k12a33kkk﹣2+13kkakkk﹣nn+1

a2{}221{}b2n124b[2﹣

4{}adaa2d

+k1aa

k2

k++1+3++3

n2n

1110a3a+4a13kkk2+1k1

1k

3

3+

k1

1

﹣

a

1k

﹣

a

1

+[1（++1]aa

[1]a22k1

111{}nan

n，

2

{

n

}3n+1

2第頁(yè)（共頁(yè)）n+1n+1nn221nn2nnn5111nnnn30n12n1nnnn1nnn1n1﹣23n123n1﹣n23nn+1n+1nn221nn2nnn5111nnnn30n12n1nnnn1nnn1n1﹣23n123n1﹣n23n1nnnnnnn1n1nn1n111nnnnn+a0a1012a

aa1{}a+12an+1n5+9+13++40372039189{}S30+d4b+10d2nN*

，為數(shù){}T6154+8+，為數(shù)

30

154+60240a}a4a3﹣aa3a33a13﹣﹣{}a3aa3aa3﹣

a+aa+aa+1+3+3+﹣

nn

n

[1+2+++1+n]

n

n

[+5+6+++2+nn]

n

，為數(shù)，為數(shù)aaa2

1

na22a2﹣﹣﹣a2{}{}

n

2bn第頁(yè)（共頁(yè)）nnnnn+1nnn1424234343nnnnn23224n11nn35711n1nnnn+1213n2nn11nn1nn1nnnnnn+1nnn1424234343nnnnn23224n11nn35711n1nnnn+1213n2nn11nn1nn1nn1n﹣nnII{}n

1n+13+4n22

2+{}S

d

t+n1

tnba12SSStq12a22a

2b2c

為奇數(shù)為偶數(shù)

c

，為數(shù)，偶數(shù)T+

1

+cc[]+1

a

3

，

21

，奇數(shù)，為數(shù){}2n+1{}a+26ad2adn2ba12+3b++bb5+5741+4+