First, the college entrance examination center

The application of arithmetic progression's or geometric progression's definition 1: it is mainly used to prove or judge that the related series is arithmetic (or equal ratio) series.

Arithmetic progression's general formula, the first few summation formulas and their applications: seeking.

; ask

; Solve a problem about ...

or

The problem of

The general formula of geometric series, the sum of the first n terms and its application: finding

; ask

; solve problems

or

The problem of

4 arithmetic progression and geometric progression's (small) comprehensive questions

The main nature of arithmetic progression and geometric progression's auxiliary role is to improve insight and simplify the problem-solving process when solving related problems.

6. Comprehensive questions combining series with functions, equations, inequalities, analytic geometry, etc.: appear in the form of advanced and intermediate exam questions, focusing on the ability to use relevant knowledge to solve comprehensive questions.

Second, the main points of knowledge

(1) arithmetic progression

1 Definition: If a series starts from the second term and the difference between each term and its previous term is equal to the same constant, then this series is called arithmetic progression, and this constant is called arithmetic progression's tolerance.

Cognition: {

} for arithmetic progression.

-

= dn ∈ n, d is a constant.

-

=d

n

2,

N ∈ n is and d is a constant.

This is a series of judgments or proofs {

} is the main foundation of arithmetic progression.

2 formula

(1) general formula:

=

+(n- 1) d: extension