S601A 等差數列

下列何者是等差數列？

Which of the following is/are arithmetic sequence(s)?

• 2, 22, 222, 2222

• 2, 12, 22, 32

• 2, 0.2, 0.02, 0.002

• 2，2，2，2

Answer explanation

2, 22, 222, 2222：22-2=20，222-22=200，所以它不是等差數列。

2, 12, 22, 32：12-2 = 10，22-12 = 10，32-22 = 10，所以它是等差數列。

2, 0.2, 0.02, 0.002：0.2 -2=-1.8，0.0=2-0.2=-0.18，所以它不是等差數列。

2，2，2，2：2-2=0，2-2=0，2-2=0，所以它是等差數列。

配對下列各項。Match the following.

• 公差=-13

  common difference=-13

• 1,3,5,7

• 公差=4

  common difference=4

• -9,-5,-1,3

• 公差=2

  common difference=2

• 8,8,8,8

• 公差=12

  common difference=12

• 52,39,26,13

• 公差=0

  common difference=0

• 12,24,36,48

若 5,x,19 是等差數列，則 x = ?

If 5,x,19 is an arithmetic sequence, then x=?

Mathematical Equivalence

ON

Mathematical Equivalence

ON

某等差數列的第 12 項為 -300。若該數列的首項是 8，求公差。

The 12th term of an arithmetic sequence is -300. If the first term of the sequence is 8, find the common difference.

Mathematical Equivalence

ON

在數列 23,3,-17,-37 中，第 4 項 (the 4th term) 是 ​ (a)   ，首 4 項之和 (the sum of the first 4 terms) 是 ​ (b)   ​。

• -37
• -28
• -20
• 80
• 23
• 3
• -17

Answer explanation

首 4 項之和 = 23+3+-17+-37 = -28。

在等差數列一課中，下列何者正確？

In the arithmetic sequences, which of the following is/are correct？

Answer explanation

請看短片，或看教科書第 1 章。

已知等差數列 -32，...，291 有 20 項，求該數列的所有項之和。

Given that the arithmetic sequence -32，...，291 has 20 terms, find the sum of the all terms of the sequence.

Mathematical Equivalence

ON

Mathematical Equivalence

ON