Series Flashcards
1
Q
arithmetic nth term Un =
A
a + (n-1)d
2
Q
arithmetic sum Sn =
A
n/2(2a+(n-1)d)
3
Q
arithmetic sum (last term) Sn =
A
n/2(a+L)
4
Q
geometric nth term Un =
A
ar^n-1 (or ar^n for money)
5
Q
increasing sequence
A
u n+1 > u n for all n values
6
Q
decreasing sequence
A
u n+1 < u n for all n values
7
Q
periodic sequence
A
U n+k = U n for all n values
and its period/order is k
