Question

dada a p.a. (1, 3/2, 2, 5/2 ,...) qual é a razão? e qual é o 12° termo?

Answer 1

Dada a p.a. (1, 3/2, 2, 5/2 ,...) qual é a razão? e qual é o 12° termo?
$\mathtt{R = A_2 - A_1} \\ \mathtt{R = 3/2 - 1} \\ \mathtt{R =1,5 - 1 } \\ \mathtt{R =0,5 } \\ \\ \boxed{\boxed{\mathtt{Resposta 1 : Raz\~ao = 0,5~~ou~~\frac{1}{2}}}}$

$\mathtt{A_n = A_1+(n-1)~.~R} \\ \mathtt{A_1_2=1+(12-1)~.~\frac{1}{2}} \\ \mathtt{A_{12}=1 + 11~.~\frac{1}{2}} \\ \mathtt{A_{12}=1+\frac{11}{2}} \\ \mathtt{A_{12}=\frac{2+11}{2}} \\ \\ \mathtt{A_{12}=\frac{13}{2}} \\ \\ \\ \boxed{\boxed{\mathtt{Resposta: A_{12}~~=~~\dfrac{13}{2}}}}$