Question

Find the sum of odd integers from 1to 2001

Answer 1

a=1
an=2001
d=2
n=??
an=a+(n-1)d
2001=1+(n-1)2
n-1=2000/2
n=1001
Sn=n/2(a+an)
S=1001/2(2002)
S=1001*1001
S=1002001

Answer 2

Answer for your question is 1001²