Question

01) Dada a P.A (18, 26, 34, 32...)

determine:

a) 8° termo

b) 19° termo

c) 30° termo

Answer 1

Termo geral da P.A:

An = a1 + ( n - 1 ) r

onde:

An = termo que ocupa a posição n

a1 = 1° termo

n = posição do termo an

r = razão ( 2° termo - 1° termo )

Cálculo:

a) 8° termo

an = 18 + ( 8 - 1 ) 8

an = 18 + 7 * 8

an = 18 + 56

an = 74

Resposta: 74

b) 19° termo:

an = 18 + ( 19 - 1 ) 8

an = 18 + 18 * 8

an = 18 + 144

an = 162

Resposta: 162

c) 30° termo

an = 18 + ( 30 - 1 ) 8

an = 18 + 29 * 8

an = 18 + 232

an = 250

Resposta: 250

Answer 2

Resposta:

8° termo

$a)a_{n} =a_{1} +(n-1) \ . \ r\\\\a_{8} =18+(8-1) \ . \ r\\\\a_{8} =18+7 \ . \ 8\\\\a_{8} =18+56\\\\a_{8} =74$

19° termo

$b)a_{n} =a_{1} +(n-1) \ . \ r\\\\a_{19} =18+(-19-1) \ . \ 8\\\\a_{19} =18+18 \ . \ 8\\\\a_{19} =18+144\\\\a_{19} =162$

30° termo

$c)a_{n} =a_{1} +(n-1) \ . \ r\\\\a_{30}=18+(30-1) \ . \ 8 \\\\a_{30} =18+29 \ . \ 8\\\\a_{30} =18+232\\\\a_{30} =250$