Find the variance of first n natural numbers.

Find the sum of first n even natural numbers.

Find the standard deviation of first 10 natural numbers.

Find the sum of first 100 natural numbers divisible by 3.

What is the sum of the cubes of first n natural numbers?

The sum of first n odd natural number is

If the mean of first n natural numbers is (5n)/2 then the value of n will be

If the mean of first n odd natural number is n^2/81 then the value of n will be

If S_1.S_2,S_3 are the sum of first n natural numbers,their squares and their cubes respectively,Show that : 9S_2^2=S_3(1+8S_1) .

A number is selected from first 100 natural numbers. Find the probability that the number is divisible by 7.

Chosse the correct one The sum of first 100 natural number is