Question

Dadas as progressões aritimeticas determine a razão e a soma dos 10 primeiros termos :

A) (2,4,6)
B) (1/2,1,3/2...)
C) (7,4,1...)
D) (1,6,11...)

Answer 1

a) 4-2 = r -> r = 2
S = ( 2+6)*3/2
S = 8*3/2
S = 12
---
b) 1-1/2 = r -> r = 1/2
S = (1/2 + 3/2)* 3/2
S = 2*3/2
S = 3
----
c) 7-4 = r = -3
S = (7+1)*3/2
S = 12
---
d) 6-1 = r = 5
S = ( 1 + 11)*3/2
S = 6*3
S = 18.

Bons estudos ^_^