Question

A) Determine o vigesimo termos de PA(8,5,2,-1,-4,-7,....)
B) Determine o trigesimo termo da PA(2,6,10,14,18,....)

Determime a soma de cada PA abaixo
A)PA (8,5,2,-1,-4,-7)
B)PA(2,6,10,14,18,22,26,30,34)
C)PA(5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5)


Me ajudem pr favor.

Answer 1

Resposta:

Explicação passo a passo:

A) Determine o vigésimo termo de PA (8,5,2,-1,-4,-7,....)

an = a1 + (n-1) r

a1 = 8

r = 5-8 = -3

n = 20

a20 = 8 + (20-1) -3

a20 = 8 + 19*-3

a20 = 8 - 57

a20 = -49

B) Determine o trigésimo termo da PA(2,6,10,14,18,....)

an = a1 + (n-1) r

a1 = 2

r = 6-2 = 4

n = 30

a30 = 2 + (30-1) 4

a30 = 2 + 29*4

a30 = 2 + 116

a30 = 118

Determine a soma de cada PA abaixo

A) PA (8,5,2,-1,-4,-7)

8+5+2 = 15

-1-4-7 = -12

15-12 = 3

B) PA (2,6,10,14,18,22,26,30,34)

2+6+10+14+18+22+26+30+34 = 162

C) PA (5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5)

28 * 5 = 140