Question

determine a razão de cada uma das P.A.s abaixo classificando-as em crescente, decrescente ou constante

a) (38,35,32,29,26..)

b) (-40,-34,-28,-22,-16..)

c) (1/7,1/7,1/7,1/7,1/7)

d) (90,80,70,60,50..)

e) (1/3,1,5/3, 7/3,3..)

f) (√3-2, √3-1, √3, √3+1,..)

Answer 1

a) (38,35,32,29,26..) : decrescente
r = a2 - a1
r = 35 - 38
r = - 3

b) (-40,-34,-28,-22,-16..) : crescente
r = a2 - a1
r = - 34 -(-40)
r = - 34 + 40
r = 6

c) (1/7,1/7,1/7,1/7,1/7) : constante
r = a2 - a1
r = 1/7 - 1/7
r = 0

d) (90,80,70,60,50..) : decrescente
r = a2. - a1
r = 80-90
r = - 10

e) (1/3,1,5/3, 7/3,3..) : crescente

r = a2 - a1
r = 1 - 1/3
r = (3-1)/3
r = 2/3

f) (√3-2, √3-1, √3, √3+1,..): crescente
r = a2 - a1
r = √3 - 1 - (√3 - 2)
r = √3 - 1 - √3 + 2
r = 1