Sequences And Series - YR2 Flashcards
1
Q
Arithmetic - First term
A
Un = a + (n-1)d
N - Position
A - First term
D - difference
2
Q
Arithmetic - Sum
A
Sn = n/2 ( 2a + (n-1)d)
3
Q
Arithemtic - Useful
A
Sn = n/2(a + L)
L- last term
4
Q
Geometric
A
Un = ar^(n-1)
5
Q
Geometric - Sum of
A
Sn = (a(1-r^n) / 1-r
R- ratio
6
Q
Geometric - First term
A
Un = ar^n-1
7
Q
Sum of infinity
A
S to infinity = a/ 1-r
8
Q
Recurrence and relations
A
Un = 2n^3 + 3
