{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

# 11_2 - a n Then S 1 = a 1 S 2 = a 1 a 2 = a 1 a 1 d = 2 a 1...

This preview shows pages 1–2. Sign up to view the full content.

Section 11.2: Arithmetic Sequences Instructor: Ms. Hoa Nguyen 1 Arithmetic Sequences An arithmetic sequence { a n } satisfies the following: a 1 a n = a n - 1 + d where a 1 is the first term, d is the common difference. 2 Find the n -th term of an arithmetic sequence Given the first term a 1 and the common difference d : a 1 a 2 = a 1 + d a 3 = a 1 + 2 d ... a n = a 1 + ( n - 1) d So, the n -th term of an arithmetic sequence is: a n = a 1 + ( n - 1) d . Example 1 : Example 2 : 1

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Example 3 : Example 4 : Example 5 : 3 Summing the terms of arithmetic sequence Let S k ( k = 1 , ..., n ) be the sum of the first k terms of an arithmetic sequence
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: { a n } . Then S 1 = a 1 S 2 = a 1 + a 2 = a 1 + ( a 1 + d ) = 2 a 1 + d S 3 = a 1 + a 2 + a 3 = a 1 + ( a 1 + d ) + ( a 1 + 2 d ) = 3 a 1 + 3 d ... S n = a 1 + a 2 + a 3 + ... + a n = a 1 + ( a 1 + d ) + ( a 1 + 2 d ) + ... + [ a 1 + ( n-1) d ] = na 1 + [1 + 2 + ... + ( n-1)] d = na 1 + n ( n-1) 2 d Note: S n = na 1 + n ( n-1) 2 d = n 2 (2 a 1 + ( n-1) d ) = n a 1 + a n 2 So, S n = na 1 + n ( n-1) 2 d . Example 6 : 2...
View Full Document

{[ snackBarMessage ]}

### Page1 / 2

11_2 - a n Then S 1 = a 1 S 2 = a 1 a 2 = a 1 a 1 d = 2 a 1...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online