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(Q6).Find the sum of :

(i) the first 1000 natural numbers

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

Using the formula S_n =

n

2

(a + l) for the sum of the first n terms of an AP, we have

S_n =

2

( + ) = × =

So, the sum of the first 1000 positive integers is .