The value of `1^2+2^2+3^2++n^2`

If the variate of a distribution takes the values 1^(2), 2^(2), 3^(2),….n^(2) with frequencies n, n-1, n-2,….3,2,1 respectively, then the mean value of the distribution is

If the variate of a distribution takes the values 1^(2), 2^(2), 3^(2),….n^(2) with frequencies n, n-1, n-2,….3,2,1 respectively, then the mean value of the distribution is

The value of 1 .1 !+2 .2 !+3 .3 !+..+n .n ! is

Find the value of (3^n × 3^(2n + 1))/(3^(2n) × 3^(n - 1))

the value of 1.1!+ 2.2!+ 3.3!+ ....+ n.n!

The value of 2^n [1.3.5....(2n - 3)(2n - 1) is

The value of i^(2n)+i^(2n+1)+i^(2n+2)+i^(2n+3), where i=sqrt(-1), is