Exploring Factorial Properties: Representations of n!, (n+1)!, and (n-1)!

In summary, we discussed the basic representations of factorials, including the recursive formula n! = n(n-1)! and the use of factorials in the binomial coefficient. We also mentioned Wilson's Theorem and the potential application of factorials in solving the Reimann-zeta hypothesis.
  • #1
nameVoid
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0
Id like to know some basic representations of factorials n!, (n+1)!,(n-1)! ext..
 
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  • #2
What exactly do you want? When you say representations do you have anything particular in mind? I can easily provide you with:
[tex]n! = n\times(n-1)! \qquad \mbox{for }n > 1[/tex]
but I'm suspecting you're looking for something a bit more interesting than that.
 
  • #3
You might find Wilson's Theorem interesting.
Combinatorial math is an interesting field where you deal a lot with factorials and their properties. Sometimes the algebra is tedious but you get interesting and useful results. Even if you don't know any group theory, everyone has seen basic counting in the form of permutations.

If you had a specific problem then do post it.
 
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  • #4
n!=n(n-1)!
(n+1)!=n!(n+1)?
(2n+4)!=(2n+4)(2n-3)!
(2n)!=2n(2n-1)!
..?
 
  • #5
nameVoid said:
n!=n(n-1)!
(n+1)!=n!(n+1)?
(2n+4)!=(2n+4)(2n-3)!
(2n)!=2n(2n-1)!
..?

Yeah, but all of that just follows from the first line.
Check out http://en.wikipedia.org/wiki/Binomial_coefficient#Recursive_formula"

The binomial coefficient ("choose function", or "nCr") is where you'll see factorials most often, at least until you solve the Reimann-zeta hypothesis.
 
Last edited by a moderator:
  • #6
nameVoid said:
n!=n(n-1)!
(n+1)!=n!(n+1)?
(2n+4)!=(2n+4)(2n-3)!
(2n)!=2n(2n-1)!
..?
Probably a typo, but (2n+4)!=(2n+4)(2n+3)!, not (2n + 4)(2n - 3)! as you had.
 

Related to Exploring Factorial Properties: Representations of n!, (n+1)!, and (n-1)!

What is the factorial of a number?

The factorial of a non-negative integer \(n\), denoted as \(n!\), is the product of all positive integers from 1 to \(n\). For example, \(5! = 5 \times 4 \times 3 \times 2 \times 1 = 120\).

What are some important properties of factorials?

Factorials possess several key properties, including:

  1. Multiplicative Property: \(n! = n \times (n-1)!\)
  2. Factorial of 0: \(0! = 1\) (by convention).
  3. Factorial of 1: \(1! = 1\).
  4. Factorial of a Negative Number: Factorials are not defined for negative integers.
  5. Factorial of a Fraction or Non-Integer: Factorials are typically defined only for non-negative integers.
  6. Growth Rate: Factorials grow rapidly with increasing \(n\), making them grow faster than exponential functions.

How does the multiplicative property of factorials work?

The multiplicative property states that \(n! = n \times (n-1)!\), which means you can compute the factorial of a number \(n\) by multiplying \(n\) with the factorial of \(n-1\). This property allows for the recursive calculation of factorials.

What is the significance of \(0!\) being defined as 1?

Defining \(0!\) as 1 is a convention that simplifies certain mathematical expressions and formulas. It ensures consistency in mathematical calculations and simplifies combinatorial calculations involving the empty set. Additionally, it allows for consistent use of factorials in mathematical formulas and series expansions.

Can factorials be calculated for non-integer values or fractions?

Factorials are typically defined and calculated only for non-negative integers. They are not defined for non-integer values or fractions. However, there are extensions such as the gamma function (\(\Gamma\)) in mathematics that generalize factorials to real and complex numbers, including non-integer values.

What are some applications of factorials in mathematics and beyond?

Factorials find applications in various areas, including combinatorics, probability theory, statistics, and calculus. They are used to calculate permutations and combinations, solve counting problems, derive Taylor series expansions, and analyze complex mathematical problems. In computer science, factorials are used in algorithms, particularly in recursive algorithms and combinatorial problems.

Are there any limitations or considerations when working with factorials?

Factorials grow very quickly as \(n\) increases, which can lead to large numbers that may exceed the capacity of standard numerical representations. When working with factorials, it's important to be mindful of computational limitations and consider alternative methods or approximations when dealing with extremely large factorials.

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