## Factorial

For students of class 11-12 (age 16+)
Dipika
Posts: 8
Joined: Wed Dec 21, 2011 12:24 pm
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### Factorial

Need the proof of 0!=1

tanvirab
Posts: 446
Joined: Tue Dec 07, 2010 2:08 am

### Re: Factorial

There is no proof, it's a definition.

sm.joty
Posts: 327
Joined: Thu Aug 18, 2011 12:42 am
Location: Dhaka

### Re: Factorial

একটা বস্তুর মধ্য থেকে একটা বস্তু একভাবেই নেয়া যায়। এবার সমাবেশ এর সুত্র ব্যবহার করে দেখ।
হার জিত চিরদিন থাকবেই
তবুও এগিয়ে যেতে হবে.........
বাধা-বিঘ্ন না পেরিয়ে
বড় হয়েছে কে কবে.........

photon
Posts: 186
Joined: Sat Feb 05, 2011 3:39 pm
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### Re: Factorial

my teacher once gave me that Proof( not by me0,
\$n! =n(n-1)!\$
Or,\$(n-1)! = n(n-1)!/n =n!/n\$
Putting n = 1, we have
\$O! = 1!/1=1\$
Try not to become a man of success but rather to become a man of value.-Albert Einstein

tanvirab
Posts: 446
Joined: Tue Dec 07, 2010 2:08 am

### Re: Factorial

photon wrote:my teacher once gave me that Proof( not by me0,
\$n! =n(n-1)!\$
Or,\$(n-1)! = n(n-1)!/n =n!/n\$
Putting n = 1, we have
\$O! = 1!/1=1\$
Here you need to define \$1!\$ first. This is also acceptable. But usually \$0!\$ is defined first then all the other positive integer factorials are derived from it.

raihan khan
Posts: 35
Joined: Wed Mar 16, 2011 12:30 pm
Location: Dhaka

### Re: Factorial

actually n things can be per mutated by n! if n is zero there is only one way to permute and it is i cannot permute. so 0!=1

tanvirab
Posts: 446
Joined: Tue Dec 07, 2010 2:08 am