Question

calcule a soma dos 50 primeiros elementos da P.A (1 , 10 , 19 ...)

Answer 1

a1=1
R=9
N=50
an=a1+(n-1)×r
a50=1+(50-1)×9
a50=1+49×9
a50=1+441
a50=442


SN=(a1+an)×n/2
SN=(1+442)×50/2
SN=443×50/2
SN=22.150/2
SN=11.075