Question

qul e a soma dps 40 primeiros termos de pa (2,8)?

Answer 1

an = a1 + (n-1)r
an = 2 + (40-1) 6
an = 2+ 39.6
an= 2 + 234
an = 236

Sn = (a1 + an)n
               2
Sn = (2 + 236) 40
                2
Sn = 238 . 20
Sn = 4 760