Question

Oblicz n-ty wyraz ciągu
a) a₁ = 25 q =⅕ n= 7
b) a₁ = 8 q= ⅔ n= 4
c) a₁= 1/10 q= 2½ n=6

Answer 1

A) a₁ = 25 q =⅕ n= 7 [wzór an=a₁*q^(n-1)]

an=25*(⅕)⁶=5²*5⁻⁶=5⁻⁴=(⅕)⁴=1/625

b) a₁ = 8 q= ⅔ n= 4

an=8*(⅔)³=2³*(⅔)³= (4/3)³ =64/27

c) a₁= 1/10 q= 2½ n=6

an=1/10* (5/2)⁵=1/10*3125/32= 3125/320