Question

whats this factorial 16! / 2! 14 !

Answer 1

14*13*12.....*1

Answer 2

what do you believe it will be? youve seen them done a few times by now right?

Answer 3

120..

Answer 4

120, yes

Answer 5

i assume its gonna be:\[\frac{16!}{2!\ 14!}\]

Answer 6

sorry

Answer 7

as long as you know what a factorial is defined by; the rest is just grade school division

Answer 8

the " ! " sign is just another notation used to express a number; it just so happend that the number it defines is equal to the product itself and the numbers below it down to 1

Answer 9

2! = 2.1
3! = 3.2.1
4! = 4.3.2.1
5! = 5.4.3.2.1


and thats the pattern to follow, start with the number they give you, and multiply it to everything that is under it

Answer 10

what about the elimination part?

Answer 11

give me an example please ?

Answer 12

the elimination part is the "grade school" division part; recall that anything over itself = 1

2/2 = 1

15/15 = 1

♫/♫ = 1

Answer 13

and anything times 1 equals itself right?

Answer 14

right

Answer 15

lets start by rewriteing these terms into something we can work with; what would we write 16! as? if you follow my examples above that is

Answer 16

16 x 15 x 14 x 13 x ....... so on & so on till you get to 1

Answer 17

right; and the 14! is the in the denominator right? im assuming it is; what is 14! written out?

Answer 18

i did this answer already
i have another one to ask you about ..

Answer 19

ok

Answer 20

20!
2! 18!

Answer 21

idk how to do the symbols sorry

Answer 22

'sok i can read it :)

Answer 23

another way to write 20! is:

20 x 19 x 18!

would you agree or disagree?

Answer 24

agree

Answer 25

goos; and also notice that: 2! = 2 x 1
= 2

20 x 19 x 18! 20 x 19
------------ = ------- ; do you agree?
2! x 18! 2

Answer 26

goos meant good lol

Answer 27

agree & 20 x 19= 308 then what do i do ?

Answer 28

i mean 380 my bad

Answer 29

we can still simplify before geting all mathical :)

20 x 19
------- = 10 x 19 , which is simply 190 then right?
2

Answer 30

right

Answer 31

380/2 is fine; but i like my numbers small

Answer 32

okayy

Answer 33

so if i multiply that that will give me my answer ?

Answer 34

or divide idk which one ?

Answer 35

we ended up with:
\[\frac{20x19}{2}=\frac{380}{2}=190\]
or
\[\frac{20x19}{2}=\frac{10x19}{1}=190\]

Answer 36

yay igot it

Answer 37

the bar indicates division

Answer 38

(n + 2) !
------
n!

Answer 39

well, lets look at it with numbers; say: n=4

(4+2)! 6x5x4!
------ = ------ = 6 x 5
4! 4!

6 = (4+2)
5 = (4+1)

so in the end it just means

(n+2) x (n+1)

n +2
n +1
-----
n^2 +2n
n +2
------------
n^2 +3n +2

Answer 40

what is ^ ?