Question

Interpole seis meios aritméticos entre -8 e 13

Answer 1

Razão da PA:

an = a1 + ( n -1) . r
13 = -8 + ( 8 -1) . r
13 = -8 + 7r
21 = 7r  
r = 3 


an = a1 + ( n -1) . r  =  an
an = -8 + ( 1 -1) .3 =  -8
an = -8 + ( 2 -1) .3  =  -5
an = -8 + ( 3 -1) .3  =  -2
an = -8 + ( 4 -1) .3  =  1
an = -8 + ( 5 -1) .3  =  4
an = -8 + ( 6 -1) .3  =  7
an = -8 + ( 7 -1) .3  =  10
an = -8 + ( 8 -1) .3  =  13


PA = ( -8, -5, -2, 1, 4, 7, 10, 13) 

Answer 2

Boa tarde!

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Dados:

a1→ -8

n → 2+6 = 8

r → ?

an → 13

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Em busca da razão da P.A :

An=a1+(n-1)·r

13=-8+(8-1)·r

13=-8+7r

13+8=7r

21=7r

r=21/7

r=3

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P.A (-8, -5, -2, 1, 4, 7, 10, 13)

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Att;Guilherme Lima