Question

Dados o termo a1 e a razão q , determine os cincos primeiros termos de cada PG :

a) a1 = -80 ; q = -1/4

b) a1 = raiz quadrada de 3 ; q = -1/4

c) a1 = 0,5 ; q = - 0,2

Answer 1

a) a 1 = -80
q = -1/4
P.G.(-80,20,-5,5/4,-5/16)
a 2 = a 1 . -1/4
a 2 = -80 . -1/4 = 80/4 = 20
a 3 = 20 . -1/4 = -20/4 = - 5
a 4 = -5 . -1/4 = 5/4
a 5 = 5/4 . -1/4 = -5/16

b)P.G.(√3 ,-√3/4,√3/16,-√3/64,√3/256)
a 1 = √3
q = -1/4
a 2 = √3 . -1/4 = -√3/4
a 3 = -√3/4  . - 1/4 = √3/16
a 4 = √3/16 . -1/4 = -√3/64
a 5 = -√3/64 . -1/4 = √3/256

c) P.G.(1/2,-1/10,-1/50,1/250,1/1250
a 1 = 1/2
q = -0,2 = -2/10 = -1/5
a 2 = 1/2 . -1/5 = -1/10
a 3 = -1/10 . -1/5 = 1/50
a 4 = 1/50 . -1/5 = -1/250
a 5 = -1/250 . -1/5 = 1/1250