Question

find the sum of odd integers from 1 to 2001.​

Answer 1

Answer:

$a=1$

$s_n = 2001$

$n \: th \: term \: is \: given \: by$

$a_n=a+(n-1)d$

$a_n=1+(n-1)2$

$2001=1+2n-2$

$2001=1+2n$

$2n=2001+1$

$2n=2001$

$n= \frac{2002}{2}$

$n=1001$

sum

$s_n= \frac{n}{2} (a + l)$

$s_n= \frac{1001}{2}(1 + 2001)$

$s_n = \frac{1001}{2}(2001)$

$s_n = 1001(1001)$

$s_n = 1002001$