# Key Words

### Selena and Jose

Fibonacci Sequence

an infinite sequence of numbers

General Term

notation that represents the "nth" term of a sequence

Graph of a sequence

set of discrete points

Recursion formula

defines the "nth term" of a function of the previous term

Factorial Notation

products of consecutive positive integers that are expressed in special notation.

example: 6! = 6x5x4x3x2x1

Summation Notation (sigma)

expressing a sum as a1+a2+a3+a4 etc etc etc

Index of Summation

(the letter "i")the sum of as "i" goes from 1-10 of a;

(N-upper limit) (1- lower limit)

Expanding the Summation Notation

written out sum that is given in summation notation

Arithmetic Sequence

a sequence in which each term after the first differs from the proceeding term by a constant amount (deals with addition)

Common difference

the difference between consecutive terms

Nth Partial Sum

the sum of the first "n" terms of an arithmetic sequence, donated by Sn

ex) Sn=a1+a2+a3+...an

Common Ratio

the amount by which we multiply each time

Value of Annuity

the sum of all deposits made plus all interests paid

Annuity

a sequence of equal payments made at equal time periods

ex) IRA

Infinite geometric series

an infinite sum of the form with first term a1 and common ratio "r"

Multiplier effect: (a1)/(1-r)