Question

Misalnya kalau , -100-99-98-....-2-1-0+1+2+...+48+49+50

Answer 1

Sn=n/2(a+Un)
Un=-100+(n-1)1
=-100+n-1
=n-101=50
n=151
S151=151/2(-100+50)
=151/2.-50=-3775