Question 1

下列何者為等差級數？

Accepted Answer

19 + 15 + 11 + 7 + 3

Answer

2，2，2，2，2

Answer

(-1) + 1 + (-1) + 1 + (-1)

Answer

3，7，11，15，19

Question 2

一等差級數的首項為 31，末項為 19，和為 600，則項數是多少？

Accepted Answer

24

Answer

25

Answer

23

Answer

21

Question 3

等差級數 2 + 5 + 8 + .....+65 = ？

Accepted Answer

737

Answer

747

Answer

767

Answer

757

Question 4

等差級數 10 + 6 + 2 + .... 至第 20 項的和為何？

Accepted Answer

-560

Answer

-580

Answer

-480

Answer

-500

Question 5

一等差級數共有 9 項，其首項為 5，公差為 -3，則總和 =？

Accepted Answer

-63

Answer

-61

Answer

-60

Answer

-62

Question 6

等差級數 100 + 97 + 94 + .... + 40 + 37 = ？

Accepted Answer

1507

Answer

1437

Answer

1544

Answer

1477

Question 7

一等差級數共 10 項，$S_{10}$ = 250，若將此級數各項加 7，則新級數之和為多少？

Accepted Answer

320

Answer

360

Answer

310

Answer

300

Question 8

一等差級數的首項為 79，末項為 19，和為 1029，則其公差為何？

Accepted Answer

-3

Answer

-4

Answer

-5

Answer

-2

Question 9

一等差級數前 n 項的和為 $S_n$，若 $S_n$=n( 2n -1 )，則此等差級數的第10項為何？

Accepted Answer

37

Answer

39

Answer

35

Answer

62

Question 10

一等差級數的第 n 項為 3n - 4，則其前10項的和為多少？

Accepted Answer

125

Answer

130

Answer

120

Answer

100

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