What are the values of a 1 and r of the geometric series? 1 + 3 + 9 + 27 + 81 a 1 = 1 and r = onethird a 1 = onethird and r = 1 a 1 = 1 and r = 3 a 1 = 3 and
Mathematics
aubreyjgagon
Question
What are the values of a 1 and r of the geometric series? 1 + 3 + 9 + 27 + 81 a 1 = 1 and r = onethird a 1 = onethird and r = 1 a 1 = 1 and r = 3 a 1 = 3 and r = 1
2 Answer

1. User Answers gmany
Answer:
a₁ = 1 and r = 3
Stepbystep explanation:
[tex]1+3+9+27+81\\\\a_1=1,\ a_2=3,\ a_3=9,\ a_4=27,\ a_5=81\\\\r=\dfrac{a_{n+1}}{a_n}\Rightarrow r=\dfrac{a_2}{a_1}=\dfrac{a_3}{a_2}=\dfrac{a_4}{a_3}=\dfrac{a_5}{a_4}\\\\r=\dfrac{3}{1}=\dfrac{9}{3}=\dfrac{27}{9}=\dfrac{81}{27}=3[/tex]

2. User Answers profarouk
Good evening ,
Answer:
a₁ = 1
r = 3
Stepbystep explanation:
Since it’s a geometric series then
a₁ = 1 ( because 1 is the first term of the series)
3/1 = 9/3 = 27/9 = 81/27 = 3 then r=3.
:)