Question -
Answer -
The odd integers from1 to 2001 are 1, 3, 5, тАж1999, 2001.
It clearly forms asequence in A.P.
Where, the firstterm,┬аa┬а= 1
Commondifference,┬аd┬а= 2
Now,
a + (n -1)d = 2001
1 + (n-1)(2) = 2001
2n тАУ 2 = 2000
2n = 2000 + 2 = 2002
n = 1001
We know,
Sn┬а=n/2 [2a + (n-1)d]
Therefore, the sum ofodd numbers from 1 to 2001 is 1002001.