Question
Find the 6th term of the arithmetic sequence given an = (1/5)an-1, given a1 = 20
Answers
Reiny
If I read this correctly as
a<sub>n</sub> = (1/5) a<sub>n-1</sub> , where <sub>1</sub> = 20
then
<sub>1</sub> = 20
<sub>2</sub> = 4
<sub>3</sub> = 4/5
etc
then this not an arithmetic but rather a geometric sequence
with a = 20 , r = 1/5
t<sub>6</sub> = ar^5 = 20(1/5)^5 = 20/3125 = 4/625
a<sub>n</sub> = (1/5) a<sub>n-1</sub> , where <sub>1</sub> = 20
then
<sub>1</sub> = 20
<sub>2</sub> = 4
<sub>3</sub> = 4/5
etc
then this not an arithmetic but rather a geometric sequence
with a = 20 , r = 1/5
t<sub>6</sub> = ar^5 = 20(1/5)^5 = 20/3125 = 4/625
Thomas
Give the arithmetic sequence -7 ,-1, 5,11. Find the a.32term b.42 term.