Question

calcule a soma dos 100 primeiros termos da pa(26,31,36,...)

Answer 1

P.A(26,31,36
R = A 2 - A 1
R = 31 - 26
R = 5
N = 100
A N = A 1 + (N - 1 ).R
A 100 = 26 + (100 - 1 ).5
A 100 = 26 + 99 . 5
A 100 = 26 + 495
A 100 = 521
S n = n.(a 1 + a n )  /2
S 100 = 100 (26 + 521 ) / 2
S 100 = 100 (547) / 2
S 100 = 54700/2
S 100 = 27350