Question

escreva uma pa de 5 termos onde a1=5 e r=-2

Answer 1

a₁ = 5

r = - 2

a₂ = 5 + (2 - 1) . (- 2) ----- a₂ = 5 - 2 ---- a₂ = 3

a₃ = 5 + 2 . (- 2) ----- a₃ = 5 - 4 ------- a₃ = 1

a₄ = 5 + 3 . (-2) ------ a₄ = 5 - 6 ----- a₄ = - 1

a₅ = 5 + 4 . (-2) ----- a₅ = 5 - 8 ------- a₅ = - 3

(5, 3, 1, -1, - 3)

Answer 2

$\mathtt{ A_n = A_1 + (n - 1)~.~R}}$

$\mathtt{A_1= 5 +(1-1)~.~(-2)~~\rightarrow ~~5+0~.~ -2~~ \rightarrow~~ 5 } \\ \\ \mathtt{A_2= 5 +(2-1)~.~(-2)~~\rightarrow ~~5+1~.~ -2~~ \rightarrow~~5-2~~\rightarrow~~3 } \\ \\ \mathtt{A_3= 5 +(3-1)~.~(-2)~~\rightarrow ~~5+2~.~ -2~~ \rightarrow~~5-4~~\rightarrow~~1 } \\ \\ \mathtt{A_4= 5 +(4-1)~.~(-2)~~\rightarrow ~~5+3~.~ -2~~ \rightarrow~~5-6~~\rightarrow~~-1 } \\ \\ \mathtt{A_5= 5 +(5-1)~.~(-2)~~\rightarrow ~~5+4~.~ -2~~ \rightarrow~~5--8~~\rightarrow~~-3 }$