If n is any positive integer, then find the number whose square is `111........1(2n` times) `- 222........2(n` times)

If n is any positive integer, then find the number whose square is underset(2n "items " ) underbrace(111.......1) - underset( "n times " ) underbrace(222.........2)

If n be any integer, then n(n+1) (2n+1) is-

If the sum of first n positive integers is 1/5 times the sum of their square then n equals

If ‘n’ be any integer ,then n(n+1)( 2n+1) is :

If ((1+i)/(1-i))^x=1 then (A) x=2n+1 , where n is any positive ineger (B) x=4n , where n is any positive integer (C) x=2n where n is any positive integer (D) x=4n+1 where n is any positive integer

Suppose n is a positive integer such that (n^2 + 48) is a perfect square. What is the number of such n? (n<5)