9-2 Formulas Flashcards
1
Q
Linear series
A
K= n(n + 1)
———–
2
2
Q
Quadratic series
A
k^2= n(n + 1)(2n + 1)
——————–
6
3
Q
Constant series
A
c= nc
4
Q
General rule for arithmetic sequences
A
an= a1 + (n-1)d
5
Q
Sum of the first n terms of an arithmetic series
A
Sn= n[(a1 + an)/2]
6
Q
General rule for geometric sequences
A
an= a1 • r^(n-1)
7
Q
Geometric mean
A
Square root of a • b
8
Q
Sun of the first n terms of a geometric series
A
Sn= A1(1-r^n / 1-r)
R doesn’t equal 1
9
Q
Sum of an infinite geometric series
A
S = A1
———
1 - r
