Question

Escreva os cincos primeiros termos da sequência A1 = 4 e an= an-1 + 5; nen*, n mais igual 2?

Answer 1

Dada a equação do termo geral, temos:

$\boxed{a_n~=~a_{n-1}+5}\\\\\\a_2~=~a_{2-1}+5\\\\a_2~=~a_1+5\\\\a_2~=~4+5\\\\\boxed{a_2~=~9}\\\\\\a_3~=~a_{3-1}+5\\\\a_3~=~a_2+5\\\\a_3~=~9+5\\\\\boxed{a_3~=~14}$

$a_4~=~a_{4-1}+5\\\\a_4~=~a_3+5\\\\a_4~=~14+5\\\\\boxed{a_4~=~19}\\\\\\a_5~=~a_{5-1}+5\\\\a_5~=~a_4+5\\\\a_5~=~19+5\\\\\boxed{a_5~=~24}$

Assim, os 5 primeiros termos são {4 , 9 , 14 , 19 , 24}