Arithmetic sequence and geometric sequence

2,5,8,11,14 ...... Item 101 is calculated a few.
This difference between each number like 3, called arithmetic sequence, 3 is to represent tolerance, and so on.

Problem solving process:
the second term is equal to 2 + 3 =
third term is equal to 6 + 2 =
4 + 2 = equal to Item 9

is provided for the first several x

x = 2 + 3 (x- 1)

encountered such problems:
1. find the law
2. All items are related to the first comparison, to find a formula that applies to all of the arithmetic sequence.

= First + an (an item number -1) x Tolerance

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Number of columns: 2,6,18,54
latter is 3 times the previous one, this series is called the geometric sequence. 3 is the common ratio.
Item 2 is equal to 2x3 = ^{. 1}
, paragraph 3 is equal to 2x3 = ²
, paragraph 4 equals 2x3 = ³ .

The first common ratio x = an ^{(an item number -1) th power}

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