Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

You are not logged in.

- Topics: Active | Unanswered

Pages: **1**

**debjit625****Member**- Registered: 2012-07-23
- Posts: 91

I can't solve this one ...

Find n ,if

Thanks

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

Debjit Roy

___________________________________________________

The essence of mathematics lies in its freedom - Georg Cantor

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 92,958

Hi;

n = 49.

Solve this:

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

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,795

hi debjit625

So you just need to solve

Bob

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

Offline

**debjit625****Member**- Registered: 2012-07-23
- Posts: 91

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

___________________________________________________

The essence of mathematics lies in its freedom - Georg Cantor

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 92,958

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.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

Offline

**debjit625****Member**- Registered: 2012-07-23
- Posts: 91

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

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 92,958

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.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

Offline

**debjit625****Member**- Registered: 2012-07-23
- Posts: 91

I know about mathisfun ,I meant some advance stuff

Thanks again...

___________________________________________________

The essence of mathematics lies in its freedom - Georg Cantor

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 92,958

Hi;

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

**In mathematics, you don't understand things. You just get used to them.**

Offline

**debjit625****Member**- Registered: 2012-07-23
- Posts: 91

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

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 92,958

Hi debjit625;

You are welcome.

**In mathematics, you don't understand things. You just get used to them.**

Offline

Pages: **1**