Question

inserir oito meios aritméticos entre 40 e -5

Answer 1

n = 10
a1 = 40
an = -5
r = ?

-5 = 40 + (10-1) . r
-5=40+9r
-45=9r
r=-5

40, 35, 30, 25, 20, 15, 10, 5, 0, -5

Answer 2

Razão da PA:

an = a1 + ( n -1) . r
-5 = 40 + ( 10 -1) . r
-5 = 40 + 9r
-45 = 9r  
r = -5


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an = a1 + ( n -1) . r  =  an
an = 40 + ( 1 -1) .-5  =  40
an = 40 + ( 2 -1) .-5  =  35
an = 40 + ( 3 -1) .-5  =  30
an = 40 + ( 4 -1) .-5  = 25
an = 40 + ( 5 -1) .-5  =  20
an = 40 + ( 6 -1) .-5  =  15
an = 40 + ( 7 -1) .-5  =  10
an = 40 + ( 8 -1) .-5 = 5
an = 40 + ( 9 -1) .-5  =  0
an = 40 + ( 10 -1) .-5  =  -5



PA = ( 40, 35, 30, 25, 20, 15, 10, 5, 0 ,-5 )