Sequences & series Flashcards
1
Q
Sn =
A
=n/2(2a +(n-1)d)
= n/2(a+l)
2
Q
arithmetic mean of a and b
A
(a+b)/2
3
Q
nth term of a GP=
A
a(n) = ar^(n-1)
4
Q
Sum of first n terms =
A
S(n)= a(r^(n)-1)/(r-1)
5
Q
geometric mean of a and b
A
(ab)^1/2
