Sequence

a sequence having a finite number of terms.

a sequence that has an infinite number of terms.

the arithmetic mean, or simply the mean or the average, is the sum of a collection of numbers divided by the count of numbers in the collection.

The terms between a^1! and a^n" of arithmetic sequence
are called arithmetic means of a^1! and a^n".

a^n= a¹•r^n-1

is a sequence of non-zero numbers where each term after the first is found by multiplying the previous one by a fixed, non-zero number called the common ratio.

FINITE

Sn=a1(1−rn)1−r,r≠1

INFINITE

S∞ = a1 / (1-r )

Quick Formula

x=√ab

Alternate Formulas

x²= ab

a x
— = —
x b