Question

calcule a soma dos termos da p.a.(1,3,5...33)

Answer 1

razão dessa p.a = 3-1 =5-3 =2
33= 1 +(n-1).2
33=1 +2n -2
2n=34
n=17 termos
Sn=n(a1 +an)/2
Sn= 17.(1 +33)/2
Sn=17.17
Sn=289