A factorial is a mathematical operation that multiplies a positive integer by all the smaller positive integers. It is denoted by the symbol !
. For example, 5! = 5 x 4 x 3 x 2 x 1 = 120
. Factorials are useful for counting the number of ways to arrange or choose objects, or for calculating probabilities.
Finding factorials on a ti-89 calculator is easy and can be done in two ways: using the !
symbol or using the factorial(
function. In this article, we will explain both methods with examples.
Using the ! symbol
The !
symbol is a built-in symbol on the ti-89 calculator that can find the factorial of any positive integer. For example, suppose we want to find the factorial of 7.
To find the factorial using the !
symbol, follow these steps:
- Press the
ON
button to turn on the calculator. - Press the
MODE
button and make sure thatEXACT
is selected for the exact/approximate mode. - Press the
HOME
button to go to the home screen. - Enter the positive integer that you want to find the factorial of. For our example, we would enter
7
. - Press the
2ND
button and then press theMATH
button to access the math menu. - Scroll down until you see the
!
symbol and pressENTER
to select it. - Press the
ENTER
button again to calculate the factorial.
The calculator will display the factorial as 5040
. This means that 7! = 5040
.
Using the factorial( function
The factorial(
function is a custom function that can be downloaded and installed on the ti-89 calculator. It can find the factorial of any positive integer or expression. For example, suppose we want to find the factorial of 2x + 1
.
To find the factorial using the factorial(
function, follow these steps:
- Download the function from this website and transfer it to your calculator using the TI Connect software.
- Press the
ON
button to turn on the calculator. - Press the
MODE
button and make sure thatEXACT
is selected for the exact/approximate mode. - Press the
HOME
button to go to the home screen. - Press the
2ND
button and then press theVAR-LINK
button to access the variable manager. - Scroll down until you see the
factorial(
function and pressENTER
to select it. - Press the
ENTER
button again to paste the function to the home screen. - Enter the positive integer or expression that you want to find the factorial of, inside the parentheses. For our example, we would enter
2X+1
. - Press the
ENTER
button to calculate the factorial.
The calculator will display the factorial as (2X+1)!
. This means that the factorial of 2x + 1
is equal to this expression.
Summary
In this article, we learned how to find factorial on a ti-89 calculator using two methods: using the !
symbol and using the factorial(
function. Factorials are useful for counting and probability problems. We hope this article was helpful and informative. For more information on factorials and other math concepts, you can check out this website.