Evaluating Summation Notation
(Function Mode) 
A shorthand notation is used to represent sums with more than a few
terms. This shorthand notation uses the Greek letter sigma
(which denotes sum). If we have a rule such as f (n)
which assigns the value f (n) to each integer n in the set of integers {j, j+1, j+2, ... k},
we can represent the sum as:
=
On the graphing calculator:
We will be using the sum feature and the seq feature to work with a general
summation.
On the
calculator, we will interpret a summation as follows:

2^{nd }STAT (LIST) → MATH
#5 sum
The format for sum is sum( list )
where list will be the terms of
the rule
.

2nd STAT (LIST) →
OPS Choose #5 seq(
The format for seq: expression,
variable,
starting value, ending value, increment.

While sequences have a domain of
natural numbers, {1, 2, 3, 4, ...}, in Func mode, the sequence command will
accept integer domain values less than one. (In Seq mode, however, the sequence command will accept only
integer domain values of 1 or greater.)



(For ease of entry, X was used as the variable in both examples above.
If you wish to use the designated variable, type it into the
calculator using the alpha
key.)

Summations and Sequences: 
Sums, such as ,
where j = 1, may represent the summation of a sequence, called
a series.

Remember, sequences have a domain
of natural numbers, {1, 2, 3, 4, ...}.
In the sequence related
problems below, the starting
value in the summation will be greater than or equal to 1.

Again, we will be using the sum and seq features of the calculator to find the summations. The
summation is interpreted as:

2^{nd }STAT (LIST) → MATH
#5 sum

2nd STAT (LIST) →
OPS Choose #5 seq(



Example 3:
Evaluate:

This example uses x as the variable,
instead of using j. The x is simply
easier to enter into the calculator.

Example
4:
Evaluate: 
This example uses n as the variable  obtained by engaging the
alpha key.

