9-2 Formulas

Question 1

Linear series

Answer 1

K= n(n + 1)
———–
2

Question 2

Quadratic series

Answer 2

k^2= n(n + 1)(2n + 1)
——————–
6

Question 3

Constant series

Answer 3

c= nc

Question 4

General rule for arithmetic sequences

Answer 4

an= a1 + (n-1)d

Question 5

Sum of the first n terms of an arithmetic series

Answer 5

Sn= n[(a1 + an)/2]

Question 6

General rule for geometric sequences

Answer 6

an= a1 • r^(n-1)

Question 7

Geometric mean

Answer 7

Square root of a • b

Question 8

Sun of the first n terms of a geometric series

Answer 8

Sn= A1(1-r^n / 1-r)

R doesn’t equal 1

Question 9

Sum of an infinite geometric series

Answer 9

S = A1
———
1 - r