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**debjit625****Member**- Registered: 2012-07-23
- Posts: 101

I can't solve this one ...

Find n ,if

Thanks

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

Debjit Roy

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The essence of mathematics lies in its freedom - Georg Cantor

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**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

Hi;

n = 49.

Solve this:

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

**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.**

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**bob bundy****Administrator**- Registered: 2010-06-20
- Posts: 8,400

hi debjit625

So you just need to solve

Bob

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

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**debjit625****Member**- Registered: 2012-07-23
- Posts: 101

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 basicDebjit Roy

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The essence of mathematics lies in its freedom - Georg Cantor

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**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

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.**

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**debjit625****Member**- Registered: 2012-07-23
- Posts: 101

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

Debjit Roy

___________________________________________________

The essence of mathematics lies in its freedom - Georg Cantor

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**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

Hi;

In order of difficulty.

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

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

**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.**

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**debjit625****Member**- Registered: 2012-07-23
- Posts: 101

I know about mathisfun ,I meant some advance stuff

Thanks again...

___________________________________________________

The essence of mathematics lies in its freedom - Georg Cantor

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**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

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.**

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**debjit625****Member**- Registered: 2012-07-23
- Posts: 101

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.

___________________________________________________

The essence of mathematics lies in its freedom - Georg Cantor

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**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

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.**

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