Find the mean of the squares of first n natural numbers. (Given `Sigma n^2 = (n(n+1)(2n+1))/(6))`

Find the sum of first n natural numbers.

Find the mean and variance of the first n natural numbers.

The arithmetic mean of first n odd natural numbers is :

Find the mean and variance for the following data:- First n natural numbers

If P(n) is the statement that the sum of first n natural numbers is divisible by n +1, prove that P(2r) is true for all r = 1, 2, 3,...... .

If P(n) is the statement “sum of first n natural numbers is divisible by n + 1", prove that P(r + 1) is true if P(r) is true.

If the sum of n natural numbers is one sixth of their squares, then n is :

Find the first five terms of the sequence whose n^(th) term is a_n = (-1)^(n + 1) 2n