Question

qual a soma dos 50 primeiros termos da pa (3,8...)

Answer 1

r = a₂ - a₁
r = 8 -3
r = 5

$A_{n} = a_{1} + (n -1) . r$
a50 = 3 + (49) . 5
a50 = 248

$S_{n} = \frac{ ( a_{1} + a_{n} ) . n}{2}$

S50 = (248 + 3) . 50/2
S50 = 251 . 25
S50 = 6275