Math Is Fun Forum

debjit625

Member

Registered: 2012-07-23

Posts: 101

Factorial Problem

I can't solve this one ...
Find n ,if

Thanks

Last edited by debjit625 (2012-12-03 20:08:48)

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Debjit Roy
___________________________________________________
The essence of mathematics lies in its freedom - Georg Cantor

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Factorial Problem

Hi;

n = 49.

Solve this:

(n+2)(n+1) = 2550

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,621

Re: Factorial Problem

hi debjit625

So you just need to solve

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

debjit625

Member

Registered: 2012-07-23

Posts: 101

Re: Factorial Problem

Ok I have seen this in my book too but ,I didn't understood how

expands into

,is their any special rules or am I missing something very basic

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Debjit Roy
___________________________________________________
The essence of mathematics lies in its freedom - Georg Cantor

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Factorial Problem

Hi;

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

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

(n+2)! = (n+2)(n+1)n!

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

debjit625

Member

Registered: 2012-07-23

Posts: 101

Re: Factorial Problem

Now I got it thanks guys, it was so simple ,my book didnt have enough of factorials its more about permutation can you guys give me some resource on factorials...

Thanks

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Debjit Roy
___________________________________________________
The essence of mathematics lies in its freedom - Georg Cantor

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Factorial Problem

Hi;

In order of difficulty.

http://www.mathsisfun.com/numbers/factorial.html

http://www.purplemath.com/modules/factorial.htm

http://www.themathpage.com/aprecalc/factorial.htm

http://en.wikipedia.org/wiki/Factorial

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

debjit625

Member

Registered: 2012-07-23

Posts: 101

Re: Factorial Problem

I know about mathisfun ,I meant some advance stuff
Thanks again...

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Debjit Roy
___________________________________________________
The essence of mathematics lies in its freedom - Georg Cantor

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Factorial Problem

Hi;

Please check post #7, they get more and more difficult.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

debjit625

Member

Registered: 2012-07-23

Posts: 101

Re: Factorial Problem

Thanks bobbym for the link http://www.themathpage.com/aprecalc/factorial.htm
as I was searching factorial problems involving variables and it had some great stuff.

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Debjit Roy
___________________________________________________
The essence of mathematics lies in its freedom - Georg Cantor

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Factorial Problem

Hi debjit625;

You are welcome.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.