Question

Find the sum of odd integers from 1 to 2001.

Answer 1

Given is an AP whose first term is 1 and d is 2 

To find : the sum of odd integers from 1 to 2001 

Now for the finding number of terms, the formula is

n = 1001 

We know that the sum of AP is given by the formula :

s = \(\frac{n}{2}\)(2a + (n-1)d)

Substituting the values in the above equation,

s = \(\frac{1001}{2}\)(2 + (1001-1)2)

s = 1002001