Question

) Escreva uma PA de 6 temos decrescente de primeiro termo igual a 100 e razão -10​

Answer 1

$a_1=100,\ r=-10\\\\ \boxed{a_n=a_k+(n-k)r}\ \therefore\ a_n=a_1+(n-1)r\ \therefore\\\\ a_n=100+(n-1)(-10)=100-10n+10\ \therefore\\\\ \boxed{a_n=10(11-n)}\\\\ a_2=10(11-2)=90\\ a_3=10(11-3)=80\\ a_4=10(11-4)=70\\ a_5=10(11-5)=60\\ a_6=10(11-6)=50\\\\ (a_1,a_2,a_3,a_4,a_5,a_6,\dots)=\boxed{(100,90,80,70,60,50,\dots)}$