Question

Find the sum of first 1000 positive integers.​

Answer 1

Answer:

let S=1+2+3+.....+1000

using the formula s(n)=n/2(a+1) for the sum of first n terms of an AP,

we have

S1000=1000/2(1000+1)

=500×1001

=500500

so, sum of first 1000 positive integers is 500500