if `D_(k) = |{:( 1,,n,,n),(2k,,n^(2)+n+1 ,,n^(2)+n),(2k-1,,n^(2),,n^(2)+n+1):}|" and " overset(n)underset(k=1)(Sigma) D_(k)=56` then n equals

if D_(k) = |{:( 1,,n,,n),(2k,,n^(2)+n+1 ,,n^(2)+n),(2k-1,,n^(2),,n^(2)+n+1):}|" and " Sigma_(k=1)^(n) D_(k)=56 then n equals

u_(n) = |{:(1,,k,,k),(2n,,k^(2)+k+1,,k^(2)+k),(2n-1,,k^(2),,k^(2)+k+1):}| and sum_(n=1)^(k) u_(n)=72 then k=

If Delta_k=|(1,n,n), (2k, n^2+n+1, n^2+n), (2k-1, n^2, n^2+n+1)| and sum_(k=1)^n Delta_k = 56, then n is equal to (i)4 (ii)6 (iii)8 (iv)none

If Delta_(k) = |(k,1,5),(k^(2),2n +1,2n +1),(k^(3),3n^(2),3n +1)|, " then " sum_(k=1)^(n) Delta_(k) is equal to

If D_k=|[1,n,n],[2k,n^2+n+2,n^2+n],[2k-1,n^2,n^2+n+2]| and sum_(k=1)^n D_k=48 ,then n equals (a)4 (b) 6 (c) 8 (d) none of these

If D_k=1nn2k n^2+n+1n^2+n2k-1n^2n^2+n+1a n dsum_(k=1)^n D_k=56. then n equals 4 b. 6 c. 8 d. none of these

If |{:(overset(n-2)underset(k=0)sum1,n(n-1),n^2),(overset(n)underset(k=1)sum1,(n+1)(n-1),n(n+1)),(overset(n-1)underset(k=1)sum1,n^2+1,n^2):}|=72 , then n is equal to

If Delta_k=|(1,n,n),(2(k-1),n(n+1),n(n-1)),(4k(k^2-1),n(n+1)(n^2-4),n(n+2)(n^2-1))|, then f(n)=sum_(k=1)^n Delta_k+n is a polynomial of degree (i)0 (ii)1 (iii)6 (iv)7

The sum, underset(n-1)overset(10)(Sigma)(n(2n+1)(2n-1))/5 is equal to.........