Question

write a programt print the sum of the series s=1-2+3+4+5+6+7...n

Answer 1

Explanation:

27 is answer

I think its help u

Answer 2

Explanation:

s=1-2+3..n

sum of 2+3+... n is

sn =n/2(t1+tn)

sn n/2(2+n)

sn=n^2+2n/2

now sn=1-n^2+2n/2

sn=2-n^2+2n/2