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2014-03-07T10:01:27-03:00
A2 - a1 = razão

- 14 - ( -16) = r

r = 2

an = a1 + ( n - 1) .r

84 = -16 + (n-1).2

84 +16 = 2n - 2

100 + 2 = 2n

n = 51

S =    \frac{(a1 + an) . n }{2}

S =    \frac{(-16 + 84 ) . 51 }{2}

Soma = 1734


3 3 3
2014-03-07T10:06:29-03:00
Sn=(a1+an).n/2
Sn=(-16+84).51/2
Sn=68.51/2
Sn=3468/2
Sn=1734
1 5 1