How can I simplify (n+3)!/(n+1)! using the property of factorials?

In summary, a factorial is a mathematical operation represented by an exclamation mark (!) that calculates the product of all positive integers less than or equal to a given number. To simplify factorials, you can use the formula n! = n x (n-1)!, but not all factorials can be simplified. Simplifying factorials is useful for making large numbers easier to work with in equations and for quicker calculations. There are also special cases for simplifying factorials, such as when the given number is 0 or a negative integer.
  • #1
Blade
12
0
How would I go about simplifying something like:
(n+3)!/(n+1)! ?
 
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  • #2
[tex]\frac{(n+3)!}{(n+1)!} = \frac{(n+3)(n+2)\cdot(n+1)!}{(n+1)!}=(n+2)(n+3) = n^2 + 5n + 6[/tex]

cookiemonster
 
  • #3


To simplify this expression, you can use the property of factorials that states: n!/(n-k)! = n(n-1)(n-2)...(n-k+1). In this case, n = n+3 and k = n+1, so the expression becomes:

(n+3)!/(n+1)! = (n+3)(n+2)(n+1)/[(n+1)n(n-1)...(3)]

The (n+1) terms in the numerator and denominator cancel out, leaving us with:

(n+3)!/(n+1)! = (n+3)(n+2)/n(n-1)...(3)

This is the simplified expression for (n+3)!/(n+1)!.
 

What is a factorial?

A factorial is a mathematical operation that calculates the product of all positive integers less than or equal to a given number. It is represented by the exclamation mark (!). For example, 5! = 5 x 4 x 3 x 2 x 1 = 120.

How do you simplify factorials?

To simplify factorials, you can use the following formula: n! = n x (n-1)!. This means that you can break down a factorial into smaller factorials until you reach a number that is already known (usually 1).

Can all factorials be simplified?

No, not all factorials can be simplified. For example, 4! = 4 x 3 x 2 x 1 cannot be simplified any further. However, some factorials can be simplified using the formula mentioned above.

Why is simplifying factorials useful?

Simplifying factorials can make large numbers easier to work with in mathematical equations. It also allows for quicker and more efficient calculations compared to using the full factorial expression.

Are there any special cases for simplifying factorials?

Yes, there are a few special cases for simplifying factorials. One is when the given number is 0, in which case the factorial is equal to 1. Another is when the given number is a negative integer, in which case the factorial is undefined.

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