You are Here: Home >< Maths

# Is this correct (maths) watch

1. Can i re-write n! as n(n-1)(n-2)! ?
2. No just try out a value for n.
Such as n=4
4!=24
4(3)(2)!=24! Therefore they aren’t the same
3. (Original post by Howie_2114)
No just try out a value for n.
Such as n=4
4!=24
4(3)(2)!=24! Therefore they aren’t the same
I mean the factorial is on the last one
so it's 4x3x2!
factorial applies to the last number
4. Yeah, provided n is greater than or equal to two
5. Is it yes or no xD. oNE SAYS yes one says no. Can someone please confirm the answer?
6. (Original post by mariejuana)
Is it yes or no xD. oNE SAYS yes one says no. Can someone please confirm the answer?
Yes.

n! = n(n-1)! = n(n-1)(n-2)! = n(n-1)(n-2)(n-3)! ... and so on
7. (Original post by Howie_2114)
No just try out a value for n.
Such as n=4
4!=24
4(3)(2)!=24! Therefore they aren’t the same
4(3)(2)! is not the same as (4*3*2)!

4(3)(2)! = 4*3*(2!) = 4*3*2 = 24
8. (Original post by Maivnek)
Yes.

n! = n(n-1)! = n(n-1)(n-2)! = n(n-1)(n-2)(n-3)! ... and so on
ok
SO i have
n(n-1)(n-2)!/ 2(n-2)!
Would it be correct to simplify it like so
n(n-1)!/2!
and could this be further simplified ?
9. (Original post by mariejuana)
ok
SO i have
n(n-1)(n-2)!/ 2(n-2)!
Would it be correct to simplify it like so
n(n-1)!/2!
and could this be further simplified ?
The exclamation marks cancel too.
You're doing factorial of n-2 divided by factorial of n-2 so you should cancel out all of those extra terms.
10. (Original post by mariejuana)
ok
SO i have
n(n-1)(n-2)!/ 2(n-2)!
Would it be correct to simplify it like so
n(n-1)!/2!
and could this be further simplified ?

This is not correct.
11. (Original post by mariejuana)
ok
SO i have
n(n-1)(n-2)!/ 2(n-2)!
Would it be correct to simplify it like so
n(n-1)!/2!
and could this be further simplified ?
One factor is common to both the numerator and denominator, so it can be removed.
n(n-1)(n-2)!/ 2(n-2)!

and remember this is the same as:
n(n-1)((n-2)!)/ 2((n-2)!)

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: February 20, 2018
Today on TSR

### The TSR A-level options discussion thread

Choosing A-levels is hard... we're here to help

### University open days

• Heriot-Watt University
School of Textiles and Design Undergraduate
Fri, 16 Nov '18
• University of Roehampton
Sat, 17 Nov '18
• Edge Hill University
Faculty of Health and Social Care Undergraduate
Sat, 17 Nov '18
Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams