this can be done by PnC
let solve it for general
that is To show ( n! )! is divisible by ( n! )(n-1)!
take any m consective numbers let say - ( a ,a +1 ,a+2 ,..................a +m-1 )
now product of all these numbers = ( a )(a+1)................(a+m-1) = (a +m-1)! / (a-1)!
= m ! * a+m-1Cm
that mean
m consective numbers 's product is divisible by m!
as a+m-1Cm is an integer
so product of 1 to n integers is divisible by n! .............................( 1st bunch of n integers )
and product of n+1 to 2n is also divisible by n!...............................(2nd bunch of n integers )
......
....
.....
....
.... and product of n! - n+1 to n! is also divisible by n ! .........................((n-1)! bunch of n integers )
product of integers from 1 to n! = ( n ! ) !
if we take n! ( which is diviser of every bunch of n intergers ) we will get = ( n! )(n-1)!
so ( n! )! is divisible by ( n! )(n-1)!
thank u
( note - Plz try to remember this result as its very important )
this can be done by PnC
let solve it for general
that is To show ( n! )! is divisible by ( n! )(n-1)!
take any m consective numbers let say - ( a ,a +1 ,a+2 ,..................a +m-1 )
now product of all these numbers = ( a )(a+1)................(a+m-1) = (a +m-1)! / (a-1)!
= m ! * a+m-1Cm
that mean
m consective numbers 's product is divisible by m!
as a+m-1Cm is an integer
so product of 1 to n integers is divisible by n! .............................( 1st bunch of n integers )
and product of n+1 to 2n is also divisible by n!...............................(2nd bunch of n integers )
......
....
.....
....
.... and product of n! - n+1 to n! is also divisible by n ! .........................((n-1)! bunch of n integers )
product of integers from 1 to n! = ( n ! ) !
if we take n! ( which is diviser of every bunch of n intergers ) we will get = ( n! )(n-1)!
so ( n! )! is divisible by ( n! )(n-1)!
thank u
( note - Plz try to remember this result as its very important )