Question

Insira 12 meios aritméticos entre 60 e -5.

Answer 1

Resposta:

Encontrar a razão da PA

an = a1 + ( n -1) . r    

-5 = 60 + ( 14 -1) . r    

-5 = 60 + 13r    

-65 = 13r    

r = -5

===

an = a1 + ( n -1) . r = an

an = 60 + ( 1 -1) .-5 = 60

an = 60 + ( 2 -1) .-5 = 55

an = 60 + ( 3 -1) .-5 =50

an = 60 + ( 4 -1) .-5 = 45

an = 60 + ( 5 -1) .-5 = 40

an = 60 + ( 6 -1) .-5 = 35

an = 60 + ( 7 -1) .-5 = 30

an = 60 + ( 8 -1) .-5 = 25

an = 60 + ( 9 -1) .-5 = 20

an = 60 + ( 10 -1) .-5 = 15

an = 60 + ( 11 -1) .-5 = 10

an = 60 + ( 12 -1) .-5 = 5

an = 60 + ( 13 -1) .-5 = 0

an = 60 + ( 14 -1) .-5 = -5

PA = (60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, 0, -5 )

Answer 2

resolução!

an = a1 + ( n - 1 ) r

- 5 = 60 + ( 14 - 1 ) r

- 5 = 60 + 13r

- 5 - 60 = 13r

- 65 = 13r

r = - 65/13

r = - 5

PA = { 60 , 55 , 50 , 45 , 40 , 35 , 30 , 25 , 20 , 15 , 10 , 5 , 0 , - 5 }