Question

dada a p.g.(1,-1,1,-1,1,-1,1,-1...)qual a soma dos seus 51 primeiros termos

Answer 1

an= 1.(-1)^51-1
an= 1.(-1)^50
an= 1.1
an= 1

Sn= (1.(-1)-1)/-1-(-1)
Sn= (-2)/0
Sn= 0