If the sum of the first n positive integers is S , what is the sum of the first n positive even integers, in terms of S ?
let n = 5
1+2+3+4+5 = 15 = S
so first n positive intgers = 2 + 4 + 6 + 8 + 10 = 30 = 2S
....calculation mistake....u r right it is 2S...my bad.
...sum of first n even integers is n(n+1)...and sum of first n integers is n(n+1)/2