Question

convert it into factorial :- (n+1)(n+2)(n+3)..........(2n)

Answer 1

we know ,
n ! = n( n -1)(n-2)(n-3) ......2×1
or
1 × 2 × 3 .......(n -1)n

now , here ,
(n + 1)( n +2)(n +3) .......( n +n)

or

( n +n ){ n+(n -1)}.......2× 1
2n !/n! = 2n(2n-1)....(n+1)

hence ,
answer is 2n !/n!

Answer 2

Solution :-- 2n!= 1*2*3*4...........*n*(n+1)

And here we need to convert (n+1)(n+2)(n+3)...........(2n) into factorial

multiply and divide the expression by n!

So it will be n!*(n+1)*(n+2)*.........* ( 2n)/ n!

then it becomes 2n!/n!